diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index 4ea94c09d..bc2faccae 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -49,10 +49,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <set>
 #include <list>
 #include <stdarg.h> // for va_start, va_end
-
-#if TORRENT_HAS_BOOST_UNORDERED
-#include <boost/unordered_map.hpp>
-#endif
+#include <unordered_map>
 
 #ifdef TORRENT_USE_OPENSSL
 #include "libtorrent/ssl_stream.hpp"
@@ -202,11 +199,7 @@ namespace libtorrent
 			friend class libtorrent::invariant_access;
 #endif
 			typedef std::set<boost::shared_ptr<peer_connection> > connection_map;
-#if TORRENT_HAS_BOOST_UNORDERED
-			typedef boost::unordered_map<sha1_hash, boost::shared_ptr<torrent> > torrent_map;
-#else
-			typedef std::map<sha1_hash, boost::shared_ptr<torrent> > torrent_map;
-#endif
+			typedef std::unordered_map<sha1_hash, boost::shared_ptr<torrent> > torrent_map;
 
 			session_impl(io_service& ios);
 			virtual ~session_impl();
diff --git a/include/libtorrent/config.hpp b/include/libtorrent/config.hpp
index 2320152ac..ffde6fe08 100644
--- a/include/libtorrent/config.hpp
+++ b/include/libtorrent/config.hpp
@@ -587,10 +587,6 @@ int snprintf(char* buf, int len, char const* fmt, ...)
 #define TORRENT_USE_I2P 1
 #endif
 
-#ifndef TORRENT_HAS_BOOST_UNORDERED
-#define TORRENT_HAS_BOOST_UNORDERED 1
-#endif
-
 #if !defined TORRENT_IOV_MAX
 #ifdef IOV_MAX
 #define TORRENT_IOV_MAX IOV_MAX
diff --git a/include/libtorrent/file_storage.hpp b/include/libtorrent/file_storage.hpp
index 86c860a0a..b4a929a23 100644
--- a/include/libtorrent/file_storage.hpp
+++ b/include/libtorrent/file_storage.hpp
@@ -37,6 +37,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <string>
 #include <vector>
+#include <unordered_set>
 #include <ctime>
 
 #include <boost/cstdint.hpp>
@@ -498,7 +499,7 @@ namespace libtorrent
 		// levels. i.e. if one path in the torrent is ``foo/bar/baz``, the CRC32
 		// hashes for ``foo``, ``foo/bar`` and ``foo/bar/baz`` will be added to
 		// the set.
-		void all_path_hashes(boost::unordered_set<boost::uint32_t>& table) const;
+		void all_path_hashes(std::unordered_set<boost::uint32_t>& table) const;
 
 		// flags indicating various attributes for files in
 		// a file_storage.
diff --git a/include/libtorrent/kademlia/rpc_manager.hpp b/include/libtorrent/kademlia/rpc_manager.hpp
index 55c40c3ae..c41258c5e 100644
--- a/include/libtorrent/kademlia/rpc_manager.hpp
+++ b/include/libtorrent/kademlia/rpc_manager.hpp
@@ -35,23 +35,15 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
-#include <vector>
-#include <deque>
-#include <map>
+#include <unordered_map>
+
 #include <boost/cstdint.hpp>
 #include <boost/pool/pool.hpp>
 #include <boost/function/function3.hpp>
 
-#if TORRENT_HAS_BOOST_UNORDERED
-#include <boost/unordered_map.hpp>
-#else
-#include <multimap>
-#endif
-
 #include "libtorrent/aux_/disable_warnings_pop.hpp"
 
 #include <libtorrent/socket.hpp>
-#include <libtorrent/entry.hpp>
 #include <libtorrent/kademlia/node_id.hpp>
 #include <libtorrent/kademlia/observer.hpp>
 
@@ -59,7 +51,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 namespace libtorrent { namespace aux { struct session_impl; } }
 
-namespace libtorrent { struct dht_settings; }
+namespace libtorrent { struct dht_settings; class entry; }
 
 namespace libtorrent { namespace dht
 {
@@ -117,11 +109,7 @@ private:
 
 	mutable boost::pool<> m_pool_allocator;
 
-#if TORRENT_HAS_BOOST_UNORDERED
-	typedef boost::unordered_multimap<int, observer_ptr> transactions_t;
-#else
-	typedef std::multimap<int, observer_ptr> transactions_t;
-#endif
+	typedef std::unordered_multimap<int, observer_ptr> transactions_t;
 	transactions_t m_transactions;
 
 	udp_socket_interface* m_sock;
diff --git a/include/libtorrent/sha1_hash.hpp b/include/libtorrent/sha1_hash.hpp
index c86e9f446..d17fd920c 100644
--- a/include/libtorrent/sha1_hash.hpp
+++ b/include/libtorrent/sha1_hash.hpp
@@ -319,6 +319,7 @@ namespace libtorrent
 
 	};
 
+	// this is here to support usage of sha1_hash in boost unordered containers
 	typedef sha1_hash peer_id;
 	inline std::size_t hash_value(sha1_hash const& b)
 	{
@@ -349,5 +350,20 @@ namespace libtorrent
 #endif // TORRENT_USE_IOSTREAM
 }
 
+namespace std {
+
+	template <>
+	struct hash<libtorrent::sha1_hash>
+	{
+		std::size_t operator()(libtorrent::sha1_hash const& k) const
+		{
+			std::size_t ret;
+			// this is OK because sha1_hash is already a hash
+			std::memcpy(&ret, k.data(), sizeof(ret));
+			return ret;
+		}
+	};
+}
+
 #endif // TORRENT_PEER_ID_HPP_INCLUDED
 
diff --git a/src/file_storage.cpp b/src/file_storage.cpp
index c74a91101..81d234ae7 100644
--- a/src/file_storage.cpp
+++ b/src/file_storage.cpp
@@ -637,7 +637,7 @@ namespace libtorrent
 
 		template <class CRC>
 		void process_path_lowercase(
-			boost::unordered_set<boost::uint32_t>& table
+			std::unordered_set<boost::uint32_t>& table
 			, CRC crc
 			, char const* str, int len)
 		{
@@ -653,7 +653,7 @@ namespace libtorrent
 	}
 
 	void file_storage::all_path_hashes(
-		boost::unordered_set<boost::uint32_t>& table) const
+		std::unordered_set<boost::uint32_t>& table) const
 	{
 		boost::crc_optimal<32, 0x1EDC6F41, 0xFFFFFFFF, 0xFFFFFFFF, true, true> crc;
 
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index ed2b1b3ad..cdafcc4da 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -40,11 +40,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <algorithm>
 
 #if defined TORRENT_DEBUG && !defined TORRENT_DISABLE_INVARIANT_CHECKS
-#if TORRENT_HAS_BOOST_UNORDERED
-#include <boost/unordered_set.hpp>
-#else
-#include <set>
-#endif
+#include <unordered_set>
 #endif // TORRENT_DEBUG && !TORRENT_DISABLE_INVARIANT_CHECKS
 
 #include <boost/limits.hpp>
@@ -4814,7 +4810,6 @@ namespace aux {
 		}
 #endif
 
-#if TORRENT_HAS_BOOST_UNORDERED
 		sha1_hash next_lsd(0);
 		sha1_hash next_dht(0);
 		if (m_next_lsd_torrent != m_torrents.end())
@@ -4824,7 +4819,6 @@ namespace aux {
 			next_dht = m_next_dht_torrent->first;
 #endif
 		float load_factor = m_torrents.load_factor();
-#endif // TORRENT_HAS_BOOST_UNORDERED
 
 		m_torrents.insert(std::make_pair(*ih, torrent_ptr));
 
@@ -4845,7 +4839,6 @@ namespace aux {
 			bump_torrent(torrent_ptr.get());
 		}
 
-#if TORRENT_HAS_BOOST_UNORDERED
 		// if this insert made the hash grow, the iterators became invalid
 		// we need to reset them
 		if (m_torrents.load_factor() < load_factor)
@@ -4858,7 +4851,6 @@ namespace aux {
 				m_next_dht_torrent = m_torrents.find(next_dht);
 #endif
 		}
-#endif // TORRENT_HAS_BOOST_UNORDERED
 
 #ifndef TORRENT_NO_DEPRECATE
 		//deprecated in 1.2
@@ -6809,11 +6801,7 @@ namespace aux {
 			}
 		}
 
-#if TORRENT_HAS_BOOST_UNORDERED
-		boost::unordered_set<torrent*> unique_torrents;
-#else
-		std::set<torrent*> unique_torrents;
-#endif
+		std::unordered_set<torrent*> unique_torrents;
 		for (list_iterator<torrent> i = m_torrent_lru.iterate(); i.get(); i.next())
 		{
 			torrent* t = i.get();
@@ -6828,11 +6816,7 @@ namespace aux {
 
 #if defined TORRENT_EXPENSIVE_INVARIANT_CHECKS
 
-#if TORRENT_HAS_BOOST_UNORDERED
-		boost::unordered_set<int> unique;
-#else
-		std::set<int> unique;
-#endif
+		std::unordered_set<int> unique;
 #endif
 
 		int num_active_downloading = 0;
@@ -6873,11 +6857,7 @@ namespace aux {
 		TORRENT_ASSERT(num_active_downloading == m_torrent_lists[torrent_want_peers_download].size());
 		TORRENT_ASSERT(num_active_finished == m_torrent_lists[torrent_want_peers_finished].size());
 
-#if TORRENT_HAS_BOOST_UNORDERED
-		boost::unordered_set<peer_connection*> unique_peers;
-#else
-		std::set<peer_connection*> unique_peers;
-#endif
+		std::unordered_set<peer_connection*> unique_peers;
 		TORRENT_ASSERT(m_settings.get_int(settings_pack::connections_limit) > 0);
 
 		int unchokes = 0;
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index fa1c9aafb..dca6b1e2c 100644
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -58,8 +58,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <boost/bind.hpp>
 #include <boost/assert.hpp>
-#include <boost/unordered_set.hpp>
 
+#include <unordered_set>
 #include <iterator>
 #include <algorithm>
 #include <set>
@@ -520,7 +520,6 @@ namespace libtorrent
 		return true;
 	}
 
-#if TORRENT_HAS_BOOST_UNORDERED
 	struct string_hash_no_case
 	{
 		size_t operator()(std::string const& s) const
@@ -561,29 +560,6 @@ namespace libtorrent
 		}
 	};
 
-#else
-	struct string_less_no_case
-	{
-		bool operator()(std::string const& lhs, std::string const& rhs) const
-		{
-			char c1, c2;
-			char const* s1 = lhs.c_str();
-			char const* s2 = rhs.c_str();
-
-			while (*s1 != 0 || *s2 != 0)
-			{
-				c1 = to_lower(*s1);
-				c2 = to_lower(*s2);
-				if (c1 < c2) return true;
-				if (c1 > c2) return false;
-				++s1;
-				++s2;
-			}
-			return false;
-		}
-	};
-#endif
-
 	// root_dir is the name of the torrent, unless this is a single file
 	// torrent, in which case it's empty.
 	bool extract_files(bdecode_node const& list, file_storage& target
@@ -697,7 +673,7 @@ namespace libtorrent
 	{
 		INVARIANT_CHECK;
 
-		boost::unordered_set<boost::uint32_t> files;
+		std::unordered_set<boost::uint32_t> files;
 
 		std::string empty_str;
 
@@ -725,11 +701,7 @@ namespace libtorrent
 		INVARIANT_CHECK;
 		int cnt = 0;
 
-#if TORRENT_HAS_BOOST_UNORDERED
-		boost::unordered_set<std::string, string_hash_no_case, string_eq_no_case> files;
-#else
-		std::set<std::string, string_less_no_case> files;
-#endif
+		std::unordered_set<std::string, string_hash_no_case, string_eq_no_case> files;
 
 		std::vector<std::string> const& paths = m_files.paths();
 		files.reserve(paths.size() + m_files.num_files());