diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index 75c00d85d..11374b1da 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -5,6 +5,9 @@
 #include "store-api.hh"
 #include "archive.hh"
 #include "s3.hh"
+#ifdef ENABLE_S3
+#include <aws/core/client/ClientConfiguration.h>
+#endif
 
 #include <unistd.h>
 #include <fcntl.h>
@@ -496,7 +499,7 @@ struct CurlDownloader : public Downloader
             // FIXME: do this on a worker thread
             sync2async<DownloadResult>(success, failure, [&]() -> DownloadResult {
 #ifdef ENABLE_S3
-                S3Helper s3Helper;
+                S3Helper s3Helper(Aws::Region::US_EAST_1); // FIXME: make configurable
                 auto slash = request.uri.find('/', 5);
                 if (slash == std::string::npos)
                     throw nix::Error("bad S3 URI ‘%s’", request.uri);
diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 041c68c68..a110f5ade 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -52,8 +52,8 @@ static void initAWS()
     });
 }
 
-S3Helper::S3Helper()
-    : config(makeConfig())
+S3Helper::S3Helper(const string & region)
+    : config(makeConfig(region))
     , client(make_ref<Aws::S3::S3Client>(*config))
 {
 }
@@ -70,11 +70,11 @@ class RetryStrategy : public Aws::Client::DefaultRetryStrategy
     }
 };
 
-ref<Aws::Client::ClientConfiguration> S3Helper::makeConfig()
+ref<Aws::Client::ClientConfiguration> S3Helper::makeConfig(const string & region)
 {
     initAWS();
     auto res = make_ref<Aws::Client::ClientConfiguration>();
-    res->region = Aws::Region::US_EAST_1; // FIXME: make configurable
+    res->region = region;
     res->requestTimeoutMs = 600 * 1000;
     res->retryStrategy = std::make_shared<RetryStrategy>();
     return res;
@@ -140,6 +140,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         const Params & params, const std::string & bucketName)
         : S3BinaryCacheStore(params)
         , bucketName(bucketName)
+        , s3Helper(get(params, "aws-region", Aws::Region::US_EAST_1))
     {
         diskCache = getNarInfoDiskCache();
     }
diff --git a/src/libstore/s3.hh b/src/libstore/s3.hh
index 5d5d3475c..08a7fbf96 100644
--- a/src/libstore/s3.hh
+++ b/src/libstore/s3.hh
@@ -14,9 +14,9 @@ struct S3Helper
     ref<Aws::Client::ClientConfiguration> config;
     ref<Aws::S3::S3Client> client;
 
-    S3Helper();
+    S3Helper(const std::string & region);
 
-    ref<Aws::Client::ClientConfiguration> makeConfig();
+    ref<Aws::Client::ClientConfiguration> makeConfig(const std::string & region);
 
     struct DownloadResult
     {