diff --git a/src/config.h b/src/config.h
--- a/src/config.h
+++ b/src/config.h
@@ -51,6 +51,7 @@
     CFeeRate GetMinFeePerKB() const override;
 
 private:
+    uint64_t maxBlockSize;
     bool useCashAddr;
     Amount excessUTXOCharge;
     CFeeRate feePerKB;
diff --git a/src/config.cpp b/src/config.cpp
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -7,21 +7,25 @@
 #include "consensus/consensus.h"
 #include "globals.h"
 
-GlobalConfig::GlobalConfig() : useCashAddr(false) {}
+GlobalConfig::GlobalConfig() : useCashAddr(false) {
+    if (!SetMaxBlockSize(DEFAULT_MAX_BLOCK_SIZE)) {
+        throw "Default max block size is smaller than expected!";
+    }
+}
 
-bool GlobalConfig::SetMaxBlockSize(uint64_t maxBlockSize) {
+bool GlobalConfig::SetMaxBlockSize(uint64_t maxBlockSizeIn) {
     // Do not allow maxBlockSize to be set below historic 1MB limit
     // It cannot be equal either because of the "must be big" UAHF rule.
-    if (maxBlockSize <= LEGACY_MAX_BLOCK_SIZE) {
+    if (maxBlockSizeIn <= LEGACY_MAX_BLOCK_SIZE) {
         return false;
     }
 
-    nMaxBlockSize = maxBlockSize;
+    maxBlockSize = maxBlockSizeIn;
     return true;
 }
 
 uint64_t GlobalConfig::GetMaxBlockSize() const {
-    return nMaxBlockSize;
+    return maxBlockSize;
 }
 
 bool GlobalConfig::SetBlockPriorityPercentage(int64_t blockPriorityPercentage) {
diff --git a/src/globals.h b/src/globals.h
--- a/src/globals.h
+++ b/src/globals.h
@@ -7,8 +7,6 @@
 
 #include <cstdint>
 
-/** The largest block size this node will accept. */
-extern uint64_t nMaxBlockSize;
 extern uint64_t nBlockPriorityPercentage;
 
 #endif // BITCOIN_GLOBALS_H
diff --git a/src/globals.cpp b/src/globals.cpp
--- a/src/globals.cpp
+++ b/src/globals.cpp
@@ -4,8 +4,6 @@
 
 #include "globals.h"
 
-#include "consensus/consensus.h"
 #include "policy/policy.h"
 
-uint64_t nMaxBlockSize = DEFAULT_MAX_BLOCK_SIZE;
 uint64_t nBlockPriorityPercentage = DEFAULT_BLOCK_PRIORITY_PERCENTAGE;
diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -706,10 +706,7 @@
     fCheckpointsEnabled = true;
 }
 
-void CheckBlockMaxSize(const CChainParams &chainparams, uint64_t size,
-                       uint64_t expected) {
-    GlobalConfig config;
-
+void CheckBlockMaxSize(const Config &config, uint64_t size, uint64_t expected) {
     gArgs.ForceSetArg("-blockmaxsize", std::to_string(size));
 
     BlockAssembler ba(config);
@@ -718,34 +715,33 @@
 
 BOOST_AUTO_TEST_CASE(BlockAssembler_construction) {
     GlobalConfig config;
-    const CChainParams &chainparams = Params();
 
     // We are working on a fake chain and need to protect ourselves.
     LOCK(cs_main);
 
     // Test around historical 1MB (plus one byte because that's mandatory)
     config.SetMaxBlockSize(ONE_MEGABYTE + 1);
-    CheckBlockMaxSize(chainparams, 0, 1000);
-    CheckBlockMaxSize(chainparams, 1000, 1000);
-    CheckBlockMaxSize(chainparams, 1001, 1001);
-    CheckBlockMaxSize(chainparams, 12345, 12345);
+    CheckBlockMaxSize(config, 0, 1000);
+    CheckBlockMaxSize(config, 1000, 1000);
+    CheckBlockMaxSize(config, 1001, 1001);
+    CheckBlockMaxSize(config, 12345, 12345);
 
-    CheckBlockMaxSize(chainparams, ONE_MEGABYTE - 1001, ONE_MEGABYTE - 1001);
-    CheckBlockMaxSize(chainparams, ONE_MEGABYTE - 1000, ONE_MEGABYTE - 1000);
-    CheckBlockMaxSize(chainparams, ONE_MEGABYTE - 999, ONE_MEGABYTE - 999);
-    CheckBlockMaxSize(chainparams, ONE_MEGABYTE, ONE_MEGABYTE - 999);
+    CheckBlockMaxSize(config, ONE_MEGABYTE - 1001, ONE_MEGABYTE - 1001);
+    CheckBlockMaxSize(config, ONE_MEGABYTE - 1000, ONE_MEGABYTE - 1000);
+    CheckBlockMaxSize(config, ONE_MEGABYTE - 999, ONE_MEGABYTE - 999);
+    CheckBlockMaxSize(config, ONE_MEGABYTE, ONE_MEGABYTE - 999);
 
     // Test around default cap
     config.SetMaxBlockSize(DEFAULT_MAX_BLOCK_SIZE);
 
     // Now we can use the default max block size.
-    CheckBlockMaxSize(chainparams, DEFAULT_MAX_BLOCK_SIZE - 1001,
+    CheckBlockMaxSize(config, DEFAULT_MAX_BLOCK_SIZE - 1001,
                       DEFAULT_MAX_BLOCK_SIZE - 1001);
-    CheckBlockMaxSize(chainparams, DEFAULT_MAX_BLOCK_SIZE - 1000,
+    CheckBlockMaxSize(config, DEFAULT_MAX_BLOCK_SIZE - 1000,
                       DEFAULT_MAX_BLOCK_SIZE - 1000);
-    CheckBlockMaxSize(chainparams, DEFAULT_MAX_BLOCK_SIZE - 999,
+    CheckBlockMaxSize(config, DEFAULT_MAX_BLOCK_SIZE - 999,
                       DEFAULT_MAX_BLOCK_SIZE - 1000);
-    CheckBlockMaxSize(chainparams, DEFAULT_MAX_BLOCK_SIZE,
+    CheckBlockMaxSize(config, DEFAULT_MAX_BLOCK_SIZE,
                       DEFAULT_MAX_BLOCK_SIZE - 1000);
 
     // If the parameter is not specified, we use
diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3534,18 +3534,15 @@
                          "first tx is not coinbase");
     }
 
-    // Size limits.
-    auto nMaxBlockSize = config.GetMaxBlockSize();
-
     // Bail early if there is no way this block is of reasonable size.
-    if ((block.vtx.size() * MIN_TRANSACTION_SIZE) > nMaxBlockSize) {
+    if ((block.vtx.size() * MIN_TRANSACTION_SIZE) > config.GetMaxBlockSize()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false,
                          "size limits failed");
     }
 
     auto currentBlockSize =
         ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
-    if (currentBlockSize > nMaxBlockSize) {
+    if (currentBlockSize > config.GetMaxBlockSize()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false,
                          "size limits failed");
     }