diff --git a/indra/CMakeLists.txt b/indra/CMakeLists.txt
index 2dc666568d..9bd8341c5c 100644
--- a/indra/CMakeLists.txt
+++ b/indra/CMakeLists.txt
@@ -24,7 +24,12 @@ endif (NOT CMAKE_BUILD_TYPE)
 option(OPENSIM "OpenSim support" OFF)
 if (OPENSIM)
   add_definitions(-DOPENSIM=1)
-  message("compiling with OpenSim support")
+  if (SINGLEGRID)
+    add_definitions(-DSINGLEGRID=1 -DSINGLEGRID_URI=\"${SINGLEGRID_URI}\")
+    message("compiling with OpenSim support - Single Grid version (${SINGLEGRID_URI})")
+  else (SINGLEGRID)
+    message("compiling with OpenSim support")
+  endif (SINGLEGRID)
 else (OPENSIM)
   message("compiling without OpenSim support")
 endif (OPENSIM)
diff --git a/indra/newview/fsgridhandler.cpp b/indra/newview/fsgridhandler.cpp
index 4d14e46566..15d86fb839 100644
--- a/indra/newview/fsgridhandler.cpp
+++ b/indra/newview/fsgridhandler.cpp
@@ -180,15 +180,19 @@ void LLGridManager::initGrids()
 	mGridList = LLSD();
 
 	std::string grid_file  = gDirUtilp->getExpandedFilename(LL_PATH_APP_SETTINGS,  "grids.xml");
+#ifndef SINGLEGRID
 	std::string grid_user_file = gDirUtilp->getExpandedFilename(LL_PATH_USER_SETTINGS,  "grids.user.xml");
 	std::string grid_remote_file = gDirUtilp->getExpandedFilename(LL_PATH_USER_SETTINGS,  "grids.remote.xml");
 
 	mGridFile = grid_user_file;
+#endif
 
 	initSystemGrids();
+#ifndef SINGLEGRID
 	initGridList(grid_file, FINISH);
 	initGridList(grid_remote_file, FINISH);
 	initGridList(grid_user_file, FINISH);
+#endif
 
 	if(!mCommandLineDone)
 	{
@@ -263,6 +267,7 @@ void LLGridManager::initCmdLineGrids()
 	// set it as the 'selected' grid.
 	std::string grid;
 
+#ifndef SINGLEGRID
 	std::string cmd_line_grid = gSavedSettings.getString("CmdLineGridChoice");
 	if (!cmd_line_grid.empty())
 	{
@@ -294,7 +299,8 @@ void LLGridManager::initCmdLineGrids()
 		grid = gSavedSettings.getString("CurrentGrid");
 		LL_DEBUGS("GridManager") << "Setting grid from last selection " << grid << LL_ENDL;
 	}
-	
+#endif
+
 	if (grid.empty())
 	{
 		// no grid was specified so default to maingrid
@@ -1290,6 +1296,7 @@ void LLGridManager::saveGridList()
 	LLSDSerialize::toPrettyXML(output_grid_list, llsd_xml);
 	llsd_xml.close();
 }
+
 //<AW opensim>
 std::string LLGridManager::trimHypergrid(const std::string& trim)
 {
diff --git a/indra/newview/fspanellogin.cpp b/indra/newview/fspanellogin.cpp
index 61b698c746..f262733a71 100644
--- a/indra/newview/fspanellogin.cpp
+++ b/indra/newview/fspanellogin.cpp
@@ -227,6 +227,9 @@ FSPanelLogin::FSPanelLogin(const LLRect &rect,
 	
 	LLComboBox* server_choice_combo = getChild<LLComboBox>("server_combo");
 	server_choice_combo->setCommitCallback(boost::bind(&FSPanelLogin::onSelectServer, this));
+#ifdef SINGLEGRID
+	server_choice_combo->setEnabled(FALSE);
+#endif
 	
 	updateServer();
 	if(LLStartUp::getStartSLURL().getType() != LLSLURL::LOCATION)
diff --git a/indra/newview/llfloaterpreference.cpp b/indra/newview/llfloaterpreference.cpp
index 74b5c68814..480675389b 100644
--- a/indra/newview/llfloaterpreference.cpp
+++ b/indra/newview/llfloaterpreference.cpp
@@ -726,7 +726,7 @@ BOOL LLFloaterPreference::postBuild()
 // [/SL:KB]
 
 // <FS:AW  opensim preferences>
-#ifndef OPENSIM// <FS:AW optional opensim support/>
+#if !defined(OPENSIM) || defined(SINGLEGRID)// <FS:AW optional opensim support/>
 	// Hide the opensim tab if opensim isn't enabled
 	LLTabContainer* tab_container = getChild<LLTabContainer>("pref core");
 	if (tab_container)
diff --git a/indra/newview/llstartup.cpp b/indra/newview/llstartup.cpp
index 30bf125e12..cd3adf262d 100644
--- a/indra/newview/llstartup.cpp
+++ b/indra/newview/llstartup.cpp
@@ -893,6 +893,7 @@ bool idle_startup()
 		// </FS:Techwolf Lupindo>
 
 // <AW: opensim>
+#ifndef SINGLEGRID
 		if(!gSavedSettings.getBOOL("GridListDownload"))
 		{
 			sGridListRequestReady = true;
@@ -912,6 +913,10 @@ bool idle_startup()
 			std::string url = gSavedSettings.getString("GridListDownloadURL");
 			FSCoreHttpUtil::callbackHttpGet(url, last_modified, boost::bind(downloadGridlistComplete, _1), boost::bind(downloadGridlistError, _1, url));
 		}
+#else
+		sGridListRequestReady = true;
+#endif
+
 #ifdef OPENSIM // <FS:AW optional opensim support>
 		// Fetch grid infos as needed
 		LLGridManager::getInstance()->initGrids();
@@ -1654,7 +1659,7 @@ bool idle_startup()
 		// This call to LLLoginInstance::connect() starts the 
 		// authentication process.
 		login->connect(gUserCredential);
-#ifdef OPENSIM // <FS:AW optional opensim support>
+#if defined(OPENSIM) && !defined(SINGLEGRID) // <FS:AW optional opensim support>
 // <AW: opensim>
 		LLGridManager::getInstance()->saveGridList();
 // </AW: opensim>
diff --git a/indra/newview/llviewernetwork.h b/indra/newview/llviewernetwork.h
index a335f2b48a..02de79b263 100644
--- a/indra/newview/llviewernetwork.h
+++ b/indra/newview/llviewernetwork.h
@@ -32,7 +32,11 @@ const std::string SECOND_LIFE_MAIN_LABEL = "Second Life";
 const std::string SECOND_LIFE_BETA_LABEL = "Second Life Beta";
 
 // @TODO this really should be private, but is used in llslurl
+#if defined(OPENSIM) && defined(SINGLEGRID)
+const std::string MAINGRID = SINGLEGRID_URI;
+#else
 const std::string MAINGRID = "util.agni.lindenlab.com";
+#endif
 
 // <FS:AW optional opensim support>
 #ifdef OPENSIM