diff --git a/.github/workflows/actions.yml b/.github/workflows/actions.yml
index d5d909f55..be34f551e 100644
--- a/.github/workflows/actions.yml
+++ b/.github/workflows/actions.yml
@@ -167,7 +167,8 @@ jobs:
             -DUSE_SYSTEM_CRC32C=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Ubuntu` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Ubuntu`
       - name: Make
         run: cmake --build obj --config Debug --target libtransmission-test transmission-show
       - name: Test with sanitizers
@@ -217,7 +218,8 @@ jobs:
             -DUSE_SYSTEM_DEFAULT=ON \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Homebrew` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Homebrew` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Homebrew`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Homebrew` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Homebrew`
       - name: Make
         run: cmake --build obj --config Debug --target libtransmission-test transmission-show
       - name: Test with sanitizers
@@ -263,7 +265,8 @@ jobs:
             -DUSE_SYSTEM_CRC32C=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Ubuntu` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Ubuntu`
       - name: Make (Core)
         run: cmake --build obj --config Debug --target transmission 2>&1 | tee makelog
       - name: Make (Tests)
@@ -406,7 +409,8 @@ jobs:
             -DUSE_SYSTEM_DEFAULT=ON \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Homebrew` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Homebrew` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Homebrew`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Homebrew` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Homebrew`
       - name: Make
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -495,7 +499,8 @@ jobs:
             -DUSE_SYSTEM_B64=OFF `# Not packaged in Alpine` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Alpine` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Alpine` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Alpine`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Alpine` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Alpine`
       - name: Make
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -771,7 +776,8 @@ jobs:
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Debian 11` \
             -DUSE_SYSTEM_FMT=OFF `# Debian 11 package too old` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Debian 11` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Debian 11`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Debian 11` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Debian 11`
       - name: Build
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -849,7 +855,8 @@ jobs:
             -DUSE_SYSTEM_CRC32C=OFF `# Not packaged in Debian` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Debian` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Debian` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Debian`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Debian` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Debian`
       - name: Build
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -927,7 +934,8 @@ jobs:
             -DUSE_SYSTEM_DEFAULT=ON \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Fedora` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Fedora` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Fedora`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Fedora` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Fedora`
       - name: Build
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -1001,7 +1009,8 @@ jobs:
             -DUSE_SYSTEM_CRC32C=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Ubuntu` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Ubuntu`
       - name: Make
         run: cmake --build obj --config RelWithDebInfo
       - name: Test
@@ -1115,6 +1124,7 @@ jobs:
             -DUSE_SYSTEM_CRC32C=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_DHT=OFF `# Not packaged in Ubuntu` \
             -DUSE_SYSTEM_SMALL=OFF `# Not packaged in Ubuntu` \
-            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu`
+            -DUSE_SYSTEM_UTP=OFF `# Not packaged in Ubuntu` \
+            -DUSE_SYSTEM_WIDE_INTEGER=OFF `# Not packaged in Ubuntu`
       - name: Make
         run: cmake --build obj --config RelWithDebInfo -- "-k 0"
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3be3f73ba..19a6e795d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -83,6 +83,7 @@ tr_auto_option(USE_SYSTEM_MINIUPNPC "Use system miniupnpc library" ${USE_SYSTEM_
 tr_auto_option(USE_SYSTEM_NATPMP "Use system natpmp library" ${USE_SYSTEM_DEFAULT})
 tr_auto_option(USE_SYSTEM_SMALL "Use system small library" ${USE_SYSTEM_DEFAULT})
 tr_auto_option(USE_SYSTEM_UTP "Use system utp library" ${USE_SYSTEM_DEFAULT})
+tr_auto_option(USE_SYSTEM_WIDE_INTEGER "Use system WideInteger library" ${USE_SYSTEM_DEFAULT})
 tr_auto_option(USE_SYSTEM_B64 "Use system b64 library" ${USE_SYSTEM_DEFAULT})
 tr_auto_option(USE_SYSTEM_PSL "Use system psl library" ${USE_SYSTEM_DEFAULT})
 tr_auto_option(USE_SYSTEM_CRC32C "Use system crc32c library" ${USE_SYSTEM_DEFAULT})
@@ -251,7 +252,6 @@ set(SOURCE_ICONS_DIR "${PROJECT_SOURCE_DIR}/icons")
 find_package(FastFloat)
 find_package(RapidJSON)
 find_package(UtfCpp)
-find_package(WideInteger)
 
 find_package(Threads)
 find_package(PkgConfig QUIET)
@@ -610,6 +610,25 @@ target_compile_definitions(transmission::small
     INTERFACE
         SMALL_DISABLE_EXCEPTIONS=1)
 
+tr_add_external_auto_library(WIDE_INTEGER WideInteger
+    SUBPROJECT
+    SOURCE_DIR wide-integer)
+add_library(transmission::WideInteger INTERFACE IMPORTED)
+target_link_libraries(transmission::WideInteger
+    INTERFACE
+        WideInteger::WideInteger)
+include(CheckCXXSourceCompiles)
+check_cxx_source_compiles(
+"int main()
+{
+    unsigned __int128 u;
+    signed __int128 i;
+    return 0;
+}" TR_HAVE_INT128)
+target_compile_definitions(transmission::WideInteger
+    INTERFACE
+        $<$<BOOL:${TR_HAVE_INT128}>:WIDE_INTEGER_HAS_LIMB_TYPE_UINT64>)
+
 set(TR_WEB_ASSETS ${PROJECT_SOURCE_DIR}/web/public_html)
 if(REBUILD_WEB)
     tr_get_required_flag(REBUILD_WEB NPM_IS_REQUIRED)
diff --git a/cmake/FindWideInteger.cmake b/cmake/FindWideInteger.cmake
deleted file mode 100644
index 87494b0e7..000000000
--- a/cmake/FindWideInteger.cmake
+++ /dev/null
@@ -1,21 +0,0 @@
-add_library(WideInteger::WideInteger INTERFACE IMPORTED)
-
-target_include_directories(WideInteger::WideInteger
-    INTERFACE
-        ${TR_THIRD_PARTY_SOURCE_DIR}/wide-integer)
-
-set(_INT128_TEST_FILE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckInt128.c)
-file(WRITE ${_INT128_TEST_FILE}
-    "int main()
-    {
-        unsigned __int128 u;
-        signed __int128 i;
-        return 0;
-    }")
-try_compile(_HAVE_INT128
-    ${CMAKE_BINARY_DIR}
-    ${_INT128_TEST_FILE})
-target_compile_definitions(WideInteger::WideInteger
-    INTERFACE
-        $<$<BOOL:${_HAVE_INT128}>:WIDE_INTEGER_HAS_LIMB_TYPE_UINT64>
-)
diff --git a/libtransmission/CMakeLists.txt b/libtransmission/CMakeLists.txt
index eaf6e6def..8d507e63a 100644
--- a/libtransmission/CMakeLists.txt
+++ b/libtransmission/CMakeLists.txt
@@ -287,7 +287,7 @@ target_link_libraries(${TR_NAME}
         RapidJSON
         utf8::cpp
         wildmat
-        WideInteger::WideInteger
+        transmission::WideInteger
         Crc32c::crc32c
         $<$<BOOL:${WIN32}>:crypt32>
         $<$<BOOL:${WIN32}>:shlwapi>