diff --git a/src/Ledger.cpp b/src/Ledger.cpp
index f52e1f1e7..35ffc7dcf 100644
--- a/src/Ledger.cpp
+++ b/src/Ledger.cpp
@@ -24,7 +24,7 @@ SETUP_LOG();
 Ledger::Ledger(const NewcoinAddress& masterID, uint64 startAmount) : mTotCoins(startAmount), mLedgerSeq(1),
 	mCloseTime(0), mParentCloseTime(0), mCloseResolution(LEDGER_TIME_ACCURACY), mCloseFlags(0),
 	mClosed(false), mValidHash(false), mAccepted(false), mImmutable(false),
-	mTransactionMap(new SHAMap()), mAccountStateMap(new SHAMap())
+	mTransactionMap(new SHAMap(smtTRANSACTION)), mAccountStateMap(new SHAMap(smtFREE))
 {
 	// special case: put coins in root account
 	AccountState::pointer startAccount = boost::make_shared<AccountState>(masterID);
@@ -62,7 +62,7 @@ Ledger::Ledger(bool /* dummy */, Ledger& prevLedger) :
 	mTotCoins(prevLedger.mTotCoins), mLedgerSeq(prevLedger.mLedgerSeq + 1),
 	mParentCloseTime(prevLedger.mCloseTime), mCloseResolution(prevLedger.mCloseResolution),
 	mCloseFlags(0),	mClosed(false), mValidHash(false), mAccepted(false), mImmutable(false),
-	mTransactionMap(new SHAMap()), mAccountStateMap(prevLedger.mAccountStateMap->snapShot(true))
+	mTransactionMap(new SHAMap(smtTRANSACTION)), mAccountStateMap(prevLedger.mAccountStateMap->snapShot(true))
 { // Create a new ledger that follows this one
 	prevLedger.updateHash();
 	mParentHash = prevLedger.getHash();
@@ -123,8 +123,8 @@ void Ledger::setRaw(const Serializer &s)
 	updateHash();
 	if(mValidHash)
 	{
-		mTransactionMap = boost::make_shared<SHAMap>(mTransHash);
-		mAccountStateMap = boost::make_shared<SHAMap>(mAccountHash);
+		mTransactionMap = boost::make_shared<SHAMap>(smtTRANSACTION, mTransHash);
+		mAccountStateMap = boost::make_shared<SHAMap>(smtSTATE, mAccountHash);
 	}
 }
 
diff --git a/src/LedgerConsensus.cpp b/src/LedgerConsensus.cpp
index a07965ae6..c915faad7 100644
--- a/src/LedgerConsensus.cpp
+++ b/src/LedgerConsensus.cpp
@@ -27,7 +27,7 @@ SETUP_LOG();
 
 TransactionAcquire::TransactionAcquire(const uint256& hash) : PeerSet(hash, TX_ACQUIRE_TIMEOUT), mHaveRoot(false)
 {
-	mMap = boost::make_shared<SHAMap>(hash);
+	mMap = boost::make_shared<SHAMap>(smtTRANSACTION, hash);
 }
 
 void TransactionAcquire::done()
@@ -759,7 +759,7 @@ SHAMap::pointer LedgerConsensus::getTransactionTree(const uint256& hash, bool do
 			{
 				if (!hash)
 				{
-					SHAMap::pointer empty = boost::make_shared<SHAMap>();
+					SHAMap::pointer empty = boost::make_shared<SHAMap>(smtTRANSACTION);
 					mapComplete(hash, empty, false);
 					return empty;
 				}
diff --git a/src/SHAMap.cpp b/src/SHAMap.cpp
index 533b9d671..97580186e 100644
--- a/src/SHAMap.cpp
+++ b/src/SHAMap.cpp
@@ -41,14 +41,14 @@ std::size_t hash_value(const uint160& u)
 }
 
 
-SHAMap::SHAMap(uint32 seq) : mSeq(seq), mState(smsModifying)
+SHAMap::SHAMap(SHAMapType t, uint32 seq) : mSeq(seq), mState(smsModifying), mType(t)
 {
 	root = boost::make_shared<SHAMapTreeNode>(mSeq, SHAMapNode(0, uint256()));
 	root->makeInner();
 	mTNByID[*root] = root;
 }
 
-SHAMap::SHAMap(const uint256& hash) : mSeq(0), mState(smsSynching)
+SHAMap::SHAMap(SHAMapType t, const uint256& hash) : mSeq(0), mState(smsSynching), mType(t)
 { // FIXME: Need to acquire root node
 	root = boost::make_shared<SHAMapTreeNode>(mSeq, SHAMapNode(0, uint256()));
 	root->makeInner();
@@ -58,7 +58,7 @@ SHAMap::SHAMap(const uint256& hash) : mSeq(0), mState(smsSynching)
 SHAMap::pointer SHAMap::snapShot(bool isMutable)
 { // Return a new SHAMap that is an immutable snapshot of this one
   // Initially nodes are shared, but CoW is forced on both ledgers
-	SHAMap::pointer ret = boost::make_shared<SHAMap>();
+	SHAMap::pointer ret = boost::make_shared<SHAMap>(mType);
 	SHAMap& newMap = *ret;
 	newMap.mSeq = ++mSeq;
 	newMap.mTNByID = mTNByID;
@@ -808,7 +808,7 @@ BOOST_AUTO_TEST_CASE( SHAMap_test )
 	h4.SetHex("b92891fe4ef6cee585fdc6fda2e09eb4d386363158ec3321b8123e5a772c6ca8");
 	h5.SetHex("a92891fe4ef6cee585fdc6fda0e09eb4d386363158ec3321b8123e5a772c6ca7");
 
-	SHAMap sMap;
+	SHAMap sMap(smtFREE);
 	SHAMapItem i1(h1, IntToVUC(1)), i2(h2, IntToVUC(2)), i3(h3, IntToVUC(3)), i4(h4, IntToVUC(4)), i5(h5, IntToVUC(5));
 
 	if (!sMap.addItem(i2, true, false)) BOOST_FAIL("no add");
diff --git a/src/SHAMap.h b/src/SHAMap.h
index a942943b1..11c34a74d 100644
--- a/src/SHAMap.h
+++ b/src/SHAMap.h
@@ -128,6 +128,13 @@ enum SHANodeFormat
 	snfWIRE		= 2, // Compressed form used on the wire
 };
 
+enum SHAMapType
+{
+	smtTRANSACTION	=1,		// A tree of transactions
+	smtSTATE		=2,		// A tree of state nodes
+	smtFREE			=3,		// A tree not part of a ledger
+};
+
 class SHAMapTreeNode : public SHAMapNode
 {
 	friend class SHAMap;
@@ -282,6 +289,8 @@ private:
 
 	SHAMapState mState;
 
+	SHAMapType mType;
+
 protected:
 
 	void dirtyUp(std::stack<SHAMapTreeNode::pointer>& stack, const uint256& target, uint256 prevHash);
@@ -306,8 +315,8 @@ protected:
 public:
 
 	// build new map
-	SHAMap(uint32 seq = 0);
-	SHAMap(const uint256& hash);
+	SHAMap(SHAMapType t, uint32 seq = 0);
+	SHAMap(SHAMapType t, const uint256& hash);
 
 	~SHAMap() { mState = smsInvalid; }
 
diff --git a/src/SHAMapSync.cpp b/src/SHAMapSync.cpp
index baf7de950..7fdfac494 100644
--- a/src/SHAMapSync.cpp
+++ b/src/SHAMapSync.cpp
@@ -421,7 +421,7 @@ BOOST_AUTO_TEST_CASE( SHAMapSync_test )
 	srand(seed);
 
 	cLog(lsTRACE) << "Constructing maps";
-	SHAMap source, destination;
+	SHAMap source(smtFREE), destination(smtFREE);
 
 	// add random data to the source map
 	cLog(lsTRACE) << "Adding random data";