Location: Route 21 and Route 141, Jefferson Cty Reassurance shield after 141 as Route 21 widens to a divided highway. Location: Route 21 and Old Route 21, Jefferson Cty Reassurance shield after the old 21 interchange. Location: Route 21 and Route M, Jefferson Cty A few miles later, we’ll approach Route M. Location: Route 21 … Continue reading Missouri Route 21, MO-141 to MO-110