diff --git a/index.js b/index.js
index e54247d..0e4bef8 100644
--- a/index.js
+++ b/index.js
@@ -222,7 +222,7 @@ function css(css, file) {
             tasks.push(fs.outputFile(options.to, result.css))
 
             if (result.map) {
-              const mapfile = getMapfile(options.to)
+              const mapfile = getMapfile(options)
               tasks.push(fs.outputFile(mapfile, result.map))
             }
           } else process.stdout.write(result.css, 'utf8')
diff --git a/lib/getMapfile.js b/lib/getMapfile.js
index b9dd441..346fea7 100644
--- a/lib/getMapfile.js
+++ b/lib/getMapfile.js
@@ -1,4 +1,8 @@
 'use strict'
-module.exports = function getMapfile(p) {
-  return `${p}.map`
+const path = require('path')
+module.exports = function getMapfile(options) {
+  if (options.map && typeof options.map.annotation === 'string') {
+    return `${path.dirname(options.to)}/${options.map.annotation}`
+  }
+  return `${options.to}.map`
 }
diff --git a/test/map.js b/test/map.js
index b944cd5..7c3c2ba 100644
--- a/test/map.js
+++ b/test/map.js
@@ -59,16 +59,20 @@ test('--no-map disables internal sourcemaps', async t => {
 test('mapFile path is property resolved', async t => {
   const paths = [
     {
-      input: '/foo/bar.css/baz/index.css',
+      input: { to: '/foo/bar.css/baz/index.css' },
       want: '/foo/bar.css/baz/index.css.map'
     },
     {
-      input: '/foo/bar.sss/baz/index.sss',
+      input: { to: '/foo/bar.sss/baz/index.sss' },
       want: '/foo/bar.sss/baz/index.sss.map'
     },
     {
-      input: '/foo/bar.css/baz/bar.css',
+      input: { to: '/foo/bar.css/baz/bar.css' },
       want: '/foo/bar.css/baz/bar.css.map'
+    },
+    {
+      input: { map: { annotation: 'foo.map' }, to: '/foo/bar.css/baz/bar.css' },
+      want: '/foo/bar.css/baz/foo.map'
     }
   ]