diff --git a/src/xrpld/app/ledger/LedgerHistory.cpp b/src/xrpld/app/ledger/LedgerHistory.cpp
index ccec209bd4..466b7d7063 100644
--- a/src/xrpld/app/ledger/LedgerHistory.cpp
+++ b/src/xrpld/app/ledger/LedgerHistory.cpp
@@ -27,8 +27,6 @@
 
 namespace ripple {
 
-// FIXME: Need to clean up ledgers by index at some point
-
 LedgerHistory::LedgerHistory(
     beast::insight::Collector::ptr const& collector,
     Application& app)
@@ -47,6 +45,7 @@ LedgerHistory::LedgerHistory(
           std::chrono::minutes{5},
           stopwatch(),
           app_.journal("TaggedCache"))
+    , mLedgersByIndex(256)
     , j_(app.journal("LedgerHistory"))
 {
 }
@@ -68,7 +67,13 @@ LedgerHistory::insert(
     bool const alreadyHad = m_ledgers_by_hash.canonicalize_replace_cache(
         ledger->info().hash, ledger);
     if (validated)
+    {
         mLedgersByIndex[ledger->info().seq] = ledger->info().hash;
+        JLOG(j_.info()) << "LedgerHistory::insert: mLedgersByIndex size: "
+                        << mLedgersByIndex.size() << " , total size: "
+                        << mLedgersByIndex.size() *
+                (sizeof(LedgerIndex) + sizeof(LedgerHash));
+    }
 
     return alreadyHad;
 }
@@ -115,6 +120,11 @@ LedgerHistory::getLedgerBySeq(LedgerIndex index)
             "ripple::LedgerHistory::getLedgerBySeq : immutable result ledger");
         m_ledgers_by_hash.canonicalize_replace_client(ret->info().hash, ret);
         mLedgersByIndex[ret->info().seq] = ret->info().hash;
+        JLOG(j_.info())
+            << "LedgerHistory::getLedgerBySeq: mLedgersByIndex size: "
+            << mLedgersByIndex.size() << " , total size: "
+            << mLedgersByIndex.size() *
+                (sizeof(LedgerIndex) + sizeof(LedgerHash));
         return (ret->info().seq == index) ? ret : nullptr;
     }
 }
diff --git a/src/xrpld/app/ledger/LedgerHistory.h b/src/xrpld/app/ledger/LedgerHistory.h
index 33f8bf1d96..b1acc3cb2e 100644
--- a/src/xrpld/app/ledger/LedgerHistory.h
+++ b/src/xrpld/app/ledger/LedgerHistory.h
@@ -22,6 +22,7 @@
 
 #include <xrpld/app/ledger/Ledger.h>
 #include <xrpld/app/main/Application.h>
+#include <xrpld/core/detail/LRUMap.h>
 
 #include <xrpl/beast/insight/Collector.h>
 #include <xrpl/protocol/RippleLedgerHash.h>
@@ -149,7 +150,7 @@ private:
     ConsensusValidated m_consensus_validated;
 
     // Maps ledger indexes to the corresponding hash.
-    std::map<LedgerIndex, LedgerHash> mLedgersByIndex;  // validated ledgers
+    LRUMap<LedgerIndex, LedgerHash> mLedgersByIndex;  // validated ledgers
 
     beast::Journal j_;
 };
diff --git a/src/xrpld/core/detail/LRUMap.h b/src/xrpld/core/detail/LRUMap.h
new file mode 100644
index 0000000000..45e9a6b028
--- /dev/null
+++ b/src/xrpld/core/detail/LRUMap.h
@@ -0,0 +1,147 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef RIPPLE_APP_LRU_MAP_H_INCLUDED
+#define RIPPLE_APP_LRU_MAP_H_INCLUDED
+
+#include <list>
+#include <map>
+#include <utility>
+
+namespace ripple {
+
+template <typename Key, typename Value>
+class LRUMap
+{
+public:
+    explicit LRUMap(std::size_t capacity) : capacity_(capacity)
+    {
+        // TODO: check capacity_ > 0
+    }
+
+    Value&
+    operator[](Key const& key)
+    {
+        auto it = data_.find(key);
+        if (it != data_.end())
+        {
+            bump_to_front(key);
+            return it->second;
+        }
+        if (data_.size() >= capacity_)
+        {
+            Key const& lru = usage_list_.back();
+            usage_list_.pop_back();
+            data_.erase(lru);
+        }
+        usage_list_.push_front(key);
+        return data_[key];
+    }
+
+    auto
+    find(Key const& key)
+    {
+        return data_.find(key);
+    }
+    auto
+    find(Key const& key) const
+    {
+        return data_.find(key);
+    }
+
+    auto
+    begin()
+    {
+        return data_.begin();
+    }
+    auto
+    begin() const
+    {
+        return data_.begin();
+    }
+    auto
+    end()
+    {
+        return data_.end();
+    }
+    auto
+    end() const
+    {
+        return data_.end();
+    }
+
+    bool
+    erase(Key const& key)
+    {
+        auto it = data_.find(key);
+        if (it == data_.end())
+            return false;
+        for (auto list_it = usage_list_.begin(); list_it != usage_list_.end();
+             ++list_it)
+        {
+            if (*list_it == key)
+            {
+                usage_list_.erase(list_it);
+                break;
+            }
+        }
+        data_.erase(it);
+        return true;
+    }
+
+    std::size_t
+    size() const noexcept
+    {
+        return data_.size();
+    }
+    std::size_t
+    capacity() const noexcept
+    {
+        return capacity_;
+    }
+    void
+    clear()
+    {
+        data_.clear();
+        usage_list_.clear();
+    }
+
+private:
+    void
+    bump_to_front(Key const& key)
+    {
+        for (auto it = usage_list_.begin(); it != usage_list_.end(); ++it)
+        {
+            if (*it == key)
+            {
+                usage_list_.erase(it);
+                usage_list_.push_front(key);
+                return;
+            }
+        }
+    }
+
+    std::size_t capacity_;
+    std::map<Key, Value> data_;
+    std::list<Key> usage_list_;
+};
+
+}  // namespace ripple
+
+#endif
\ No newline at end of file