diff --git a/packages/turf-isolines/index.ts b/packages/turf-isolines/index.ts
index 6ed03bfd02..53098de9a2 100644
--- a/packages/turf-isolines/index.ts
+++ b/packages/turf-isolines/index.ts
@@ -1,5 +1,4 @@
 import bbox from "@turf/bbox";
-import clone from "@turf/clone";
 import { coordEach } from "@turf/meta";
 import { collectionOf } from "@turf/invariant";
 import { multiLineString, featureCollection, isObject } from "@turf/helpers";
@@ -157,35 +156,11 @@ function rescaleIsolines(
     point[1] = point[1] * scaleY + y0;
   };
 
-  // Ok. We need to *clone* the returned isolines due to the behaviour of
-  // the marchingsquare library behaviour. Long story short, if we don't
-  // do this, the last point in some isoLines has the coordEach function
-  // run twice, leading to one point in the isoline rendering WAY out of
-  // position.
-  const clonedIsoLines: Feature<MultiLineString>[] = [];
-  createdIsoLines.forEach((isoline) => {
-    clonedIsoLines.push(clone(isoline));
-  });
-
   // resize and shift each point/line of the createdIsoLines
-  clonedIsoLines.forEach((isoline) => {
+  createdIsoLines.forEach((isoline) => {
     coordEach(isoline, resize);
   });
-  return clonedIsoLines;
+  return createdIsoLines;
 }
 
-/*
- * A bit more background on the isoContours behaviour described above. It
- * seems like in some cases the last coord of the line references the same
- * coord array as the first point. This just seems to be the way they're
- * returned from the library:
- * [0] -> A
- * [1] -> B
- * [2] -> C
- * [3] -> A
- * Running coordEach over this mutates the values in A, then B and C, then
- * mutates [3] which happens to also be a reference to A. So the rescale
- * transform is run twice on that coord.
- */
-
 export default isolines;
diff --git a/packages/turf-isolines/lib/marchingsquares-isocontours.js b/packages/turf-isolines/lib/marchingsquares-isocontours.js
deleted file mode 100644
index 22869e863a..0000000000
--- a/packages/turf-isolines/lib/marchingsquares-isocontours.js
+++ /dev/null
@@ -1,404 +0,0 @@
-/**
- * @license GNU Affero General Public License.
- * Copyright (c) 2015, 2015 Ronny Lorenz <ronny@tbi.univie.ac.at>
- * v. 1.2.0
- * https://github.com/RaumZeit/MarchingSquares.js
- *
- * MarchingSquaresJS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * MarchingSquaresJS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * As additional permission under GNU Affero General Public License version 3
- * section 7, third-party projects (personal or commercial) may distribute,
- * include, or link against UNMODIFIED VERSIONS of MarchingSquaresJS without the
- * requirement that said third-party project for that reason alone becomes
- * subject to any requirement of the GNU Affero General Public License version 3.
- * Any modifications to MarchingSquaresJS, however, must be shared with the public
- * and made available.
- *
- * In summary this:
- * - allows you to use MarchingSquaresJS at no cost
- * - allows you to use MarchingSquaresJS for both personal and commercial purposes
- * - allows you to distribute UNMODIFIED VERSIONS of MarchingSquaresJS under any
- *   license as long as this license notice is included
- * - enables you to keep the source code of your program that uses MarchingSquaresJS
- *   undisclosed
- * - forces you to share any modifications you have made to MarchingSquaresJS,
- *   e.g. bug-fixes
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with MarchingSquaresJS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-/**
- * Compute the isocontour(s) of a scalar 2D field given
- * a certain threshold by applying the Marching Squares
- * Algorithm. The function returns a list of path coordinates
- */
-var defaultSettings = {
-  successCallback: null,
-  verbose: false,
-};
-
-var settings = {};
-
-export default function isoContours(data, threshold, options) {
-  /* process options */
-  options = options ? options : {};
-
-  var optionKeys = Object.keys(defaultSettings);
-
-  for (var i = 0; i < optionKeys.length; i++) {
-    var key = optionKeys[i];
-    var val = options[key];
-    val =
-      typeof val !== "undefined" && val !== null ? val : defaultSettings[key];
-
-    settings[key] = val;
-  }
-
-  if (settings.verbose)
-    console.log(
-      "MarchingSquaresJS-isoContours: computing isocontour for " + threshold
-    );
-
-  var ret = contourGrid2Paths(computeContourGrid(data, threshold));
-
-  if (typeof settings.successCallback === "function")
-    settings.successCallback(ret);
-
-  return ret;
-}
-
-/*
-  Thats all for the public interface, below follows the actual
-  implementation
-*/
-
-/*
-################################
-Isocontour implementation below
-################################
-*/
-
-/* assume that x1 == 1 &&  x0 == 0 */
-function interpolateX(y, y0, y1) {
-  return (y - y0) / (y1 - y0);
-}
-
-/* compute the isocontour 4-bit grid */
-function computeContourGrid(data, threshold) {
-  var rows = data.length - 1;
-  var cols = data[0].length - 1;
-  var ContourGrid = { rows: rows, cols: cols, cells: [] };
-
-  for (var j = 0; j < rows; ++j) {
-    ContourGrid.cells[j] = [];
-    for (var i = 0; i < cols; ++i) {
-      /* compose the 4-bit corner representation */
-      var cval = 0;
-
-      var tl = data[j + 1][i];
-      var tr = data[j + 1][i + 1];
-      var br = data[j][i + 1];
-      var bl = data[j][i];
-
-      if (isNaN(tl) || isNaN(tr) || isNaN(br) || isNaN(bl)) {
-        continue;
-      }
-      cval |= tl >= threshold ? 8 : 0;
-      cval |= tr >= threshold ? 4 : 0;
-      cval |= br >= threshold ? 2 : 0;
-      cval |= bl >= threshold ? 1 : 0;
-
-      /* resolve ambiguity for cval == 5 || 10 via averaging */
-      var flipped = false;
-      if (cval === 5 || cval === 10) {
-        var average = (tl + tr + br + bl) / 4;
-        if (cval === 5 && average < threshold) {
-          cval = 10;
-          flipped = true;
-        } else if (cval === 10 && average < threshold) {
-          cval = 5;
-          flipped = true;
-        }
-      }
-
-      /* add cell to ContourGrid if it contains edges */
-      if (cval !== 0 && cval !== 15) {
-        var top, bottom, left, right;
-        top = bottom = left = right = 0.5;
-        /* interpolate edges of cell */
-        if (cval === 1) {
-          left = 1 - interpolateX(threshold, tl, bl);
-          bottom = 1 - interpolateX(threshold, br, bl);
-        } else if (cval === 2) {
-          bottom = interpolateX(threshold, bl, br);
-          right = 1 - interpolateX(threshold, tr, br);
-        } else if (cval === 3) {
-          left = 1 - interpolateX(threshold, tl, bl);
-          right = 1 - interpolateX(threshold, tr, br);
-        } else if (cval === 4) {
-          top = interpolateX(threshold, tl, tr);
-          right = interpolateX(threshold, br, tr);
-        } else if (cval === 5) {
-          top = interpolateX(threshold, tl, tr);
-          right = interpolateX(threshold, br, tr);
-          bottom = 1 - interpolateX(threshold, br, bl);
-          left = 1 - interpolateX(threshold, tl, bl);
-        } else if (cval === 6) {
-          bottom = interpolateX(threshold, bl, br);
-          top = interpolateX(threshold, tl, tr);
-        } else if (cval === 7) {
-          left = 1 - interpolateX(threshold, tl, bl);
-          top = interpolateX(threshold, tl, tr);
-        } else if (cval === 8) {
-          left = interpolateX(threshold, bl, tl);
-          top = 1 - interpolateX(threshold, tr, tl);
-        } else if (cval === 9) {
-          bottom = 1 - interpolateX(threshold, br, bl);
-          top = 1 - interpolateX(threshold, tr, tl);
-        } else if (cval === 10) {
-          top = 1 - interpolateX(threshold, tr, tl);
-          right = 1 - interpolateX(threshold, tr, br);
-          bottom = interpolateX(threshold, bl, br);
-          left = interpolateX(threshold, bl, tl);
-        } else if (cval === 11) {
-          top = 1 - interpolateX(threshold, tr, tl);
-          right = 1 - interpolateX(threshold, tr, br);
-        } else if (cval === 12) {
-          left = interpolateX(threshold, bl, tl);
-          right = interpolateX(threshold, br, tr);
-        } else if (cval === 13) {
-          bottom = 1 - interpolateX(threshold, br, bl);
-          right = interpolateX(threshold, br, tr);
-        } else if (cval === 14) {
-          left = interpolateX(threshold, bl, tl);
-          bottom = interpolateX(threshold, bl, br);
-        } else {
-          console.log(
-            "MarchingSquaresJS-isoContours: Illegal cval detected: " + cval
-          );
-        }
-        ContourGrid.cells[j][i] = {
-          cval: cval,
-          flipped: flipped,
-          top: top,
-          right: right,
-          bottom: bottom,
-          left: left,
-        };
-      }
-    }
-  }
-
-  return ContourGrid;
-}
-
-function isSaddle(cell) {
-  return cell.cval === 5 || cell.cval === 10;
-}
-
-function isTrivial(cell) {
-  return cell.cval === 0 || cell.cval === 15;
-}
-
-function clearCell(cell) {
-  if (!isTrivial(cell) && cell.cval !== 5 && cell.cval !== 10) {
-    cell.cval = 15;
-  }
-}
-
-function getXY(cell, edge) {
-  if (edge === "top") {
-    return [cell.top, 1.0];
-  } else if (edge === "bottom") {
-    return [cell.bottom, 0.0];
-  } else if (edge === "right") {
-    return [1.0, cell.right];
-  } else if (edge === "left") {
-    return [0.0, cell.left];
-  }
-}
-
-function contourGrid2Paths(grid) {
-  var paths = [];
-  var path_idx = 0;
-  var epsilon = 1e-7;
-
-  grid.cells.forEach(function (g, j) {
-    g.forEach(function (gg, i) {
-      if (typeof gg !== "undefined" && !isSaddle(gg) && !isTrivial(gg)) {
-        var p = tracePath(grid.cells, j, i);
-        var merged = false;
-        /* we may try to merge paths at this point */
-        if (p.info === "mergeable") {
-          /*
-            search backwards through the path array to find an entry
-            that starts with where the current path ends...
-          */
-          var x = p.path[p.path.length - 1][0],
-            y = p.path[p.path.length - 1][1];
-
-          for (var k = path_idx - 1; k >= 0; k--) {
-            if (
-              Math.abs(paths[k][0][0] - x) <= epsilon &&
-              Math.abs(paths[k][0][1] - y) <= epsilon
-            ) {
-              for (var l = p.path.length - 2; l >= 0; --l) {
-                paths[k].unshift(p.path[l]);
-              }
-              merged = true;
-              break;
-            }
-          }
-        }
-        if (!merged) paths[path_idx++] = p.path;
-      }
-    });
-  });
-
-  return paths;
-}
-
-/*
-  construct consecutive line segments from starting cell by
-  walking arround the enclosed area clock-wise
-  */
-function tracePath(grid, j, i) {
-  var maxj = grid.length;
-  var p = [];
-  var dxContour = [0, 0, 1, 1, 0, 0, 0, 0, -1, 0, 1, 1, -1, 0, -1, 0];
-  var dyContour = [0, -1, 0, 0, 1, 1, 1, 1, 0, -1, 0, 0, 0, -1, 0, 0];
-  var dx, dy;
-  var startEdge = [
-    "none",
-    "left",
-    "bottom",
-    "left",
-    "right",
-    "none",
-    "bottom",
-    "left",
-    "top",
-    "top",
-    "none",
-    "top",
-    "right",
-    "right",
-    "bottom",
-    "none",
-  ];
-  var nextEdge = [
-    "none",
-    "bottom",
-    "right",
-    "right",
-    "top",
-    "top",
-    "top",
-    "top",
-    "left",
-    "bottom",
-    "right",
-    "right",
-    "left",
-    "bottom",
-    "left",
-    "none",
-  ];
-  var edge;
-
-  var currentCell = grid[j][i];
-
-  var cval = currentCell.cval;
-  var edge = startEdge[cval];
-
-  var pt = getXY(currentCell, edge);
-
-  /* push initial segment */
-  p.push([i + pt[0], j + pt[1]]);
-  edge = nextEdge[cval];
-  pt = getXY(currentCell, edge);
-  p.push([i + pt[0], j + pt[1]]);
-  clearCell(currentCell);
-
-  /* now walk arround the enclosed area in clockwise-direction */
-  var k = i + dxContour[cval];
-  var l = j + dyContour[cval];
-  var prev_cval = cval;
-
-  while (k >= 0 && l >= 0 && l < maxj && (k != i || l != j)) {
-    currentCell = grid[l][k];
-    if (typeof currentCell === "undefined") {
-      /* path ends here */
-      //console.log(k + " " + l + " is undefined, stopping path!");
-      break;
-    }
-    cval = currentCell.cval;
-    if (cval === 0 || cval === 15) {
-      return { path: p, info: "mergeable" };
-    }
-    edge = nextEdge[cval];
-    dx = dxContour[cval];
-    dy = dyContour[cval];
-    if (cval === 5 || cval === 10) {
-      /* select upper or lower band, depending on previous cells cval */
-      if (cval === 5) {
-        if (currentCell.flipped) {
-          /* this is actually a flipped case 10 */
-          if (dyContour[prev_cval] === -1) {
-            edge = "left";
-            dx = -1;
-            dy = 0;
-          } else {
-            edge = "right";
-            dx = 1;
-            dy = 0;
-          }
-        } else {
-          /* real case 5 */
-          if (dxContour[prev_cval] === -1) {
-            edge = "bottom";
-            dx = 0;
-            dy = -1;
-          }
-        }
-      } else if (cval === 10) {
-        if (currentCell.flipped) {
-          /* this is actually a flipped case 5 */
-          if (dxContour[prev_cval] === -1) {
-            edge = "top";
-            dx = 0;
-            dy = 1;
-          } else {
-            edge = "bottom";
-            dx = 0;
-            dy = -1;
-          }
-        } else {
-          /* real case 10 */
-          if (dyContour[prev_cval] === 1) {
-            edge = "left";
-            dx = -1;
-            dy = 0;
-          }
-        }
-      }
-    }
-    pt = getXY(currentCell, edge);
-    p.push([k + pt[0], l + pt[1]]);
-    clearCell(currentCell);
-    k += dx;
-    l += dy;
-    prev_cval = cval;
-  }
-
-  return { path: p, info: "closed" };
-}
diff --git a/packages/turf-isolines/test.js b/packages/turf-isolines/test.js
index 5f9bf4658e..f90b3acb60 100644
--- a/packages/turf-isolines/test.js
+++ b/packages/turf-isolines/test.js
@@ -79,7 +79,7 @@ test("isolines - skipping first break, from issue #2129", (t) => {
     })
   );
 
-  // Make sure an isoline is created for each break, and that it's
+  // Make sure an isoline is created for each break, and that its
   // geometry isn't empty.
   t.equal(lines.features[0].properties.name, "break5");
   t.assert(lines.features[0].geometry.coordinates[0].length > 1);