diff --git a/src/bisector.js b/src/bisector.js
index 07e4c34..d9b764e 100644
--- a/src/bisector.js
+++ b/src/bisector.js
@@ -23,7 +23,7 @@ export default function bisector(f) {
     if (lo < hi) {
       if (compare1(x, x) !== 0) return hi;
       do {
-        const mid = (lo + hi) >>> 1;
+        const mid = Math.trunc((lo + hi) / 2);
         if (compare2(a[mid], x) < 0) lo = mid + 1;
         else hi = mid;
       } while (lo < hi);
@@ -35,7 +35,7 @@ export default function bisector(f) {
     if (lo < hi) {
       if (compare1(x, x) !== 0) return hi;
       do {
-        const mid = (lo + hi) >>> 1;
+        const mid = Math.trunc((lo + hi) / 2);
         if (compare2(a[mid], x) <= 0) lo = mid + 1;
         else hi = mid;
       } while (lo < hi);
diff --git a/test/bisect-test.js b/test/bisect-test.js
index cf45842..bb0e452 100644
--- a/test/bisect-test.js
+++ b/test/bisect-test.js
@@ -165,3 +165,21 @@ it("bisectRight(array, value, lo, hi) keeps non-comparable values to the right",
   assert.strictEqual(bisectRight(values, undefined), 4);
   assert.strictEqual(bisectRight(values, NaN), 4);
 });
+
+it("bisectRight(array, value) terminates for arrays larger than 2³¹ elements (#261)", () => {
+  // A virtual sorted array of length > 2³¹, without allocating it. Reading past
+  // ~log2(length) elements means the midpoint overflowed and the search stalls.
+  const length = 2 ** 32 - 1;
+  const threshold = 3e9; // a[i] = i < threshold ? 0 : 1; boundary is above 2³¹
+  let reads = 0;
+  const a = new Proxy({}, {get(_, k) {
+    if (k === "length") return length;
+    const i = Number(k);
+    if (Number.isInteger(i)) {
+      if (++reads > 64) throw new Error("bisect did not converge");
+      return i < threshold ? 0 : 1;
+    }
+  }});
+  assert.strictEqual(bisectRight(a, 0), threshold);
+  assert.strictEqual(bisectLeft(a, 1), threshold);
+});