View of the 'Battle that saved Washington' wayside marker at Monocacy

‘The Battle That Saved Washington’ wayside markerĀ is at a scenic overlook on the Interstate 270 expressway (westbound lanes only) about 2.5 miles north of the Maryland Route 80 exit for Urbana. (39.349552 N, 77.389906 W; map)

A marker on the “Clustered Spires of Frederick” is nearby.

The 'Battle that saved Washington' marker

The ‘Battle that saved Washington’ marker (click to enlarge)

From the marker:

The Battle That Saved Washington

The Battle of Monocacy took place on July 9, 1864, in the valley before you. The battle pitted North against South, and Washington, D.C., was the prize.

Richmond and Petersburg were endangered, but the Southern leader, General Robert E. Lee had sent General Early north to threaten Washington, D.C., at least to force the Union commander at Richmond, Lieutenant General Ulysses S. Grant, to send soldiers back to defend the Capital.

The Battle of Monocacy was fought on Saturday, July 9, 1864. The Union forces were heavily outnumbered, about 18,000 to 6,000. Union General Lew Wallace gave battle to delay the Southern forces until Northern reinforcements could reach Washington, D.C.
The fighting started in mid-morning and continued throughout the day. In the late afternoon when Southern troops in battle line streamed out of the woods on Brooks Hill, broke the Northern lines and forced Wallace’s small force back towards Baltimore.

The way to Washington was open, but it was too late. General Grant summed up the importance of the valiant effort by outnumbered Northerners.

“They met the enemy, and, as might have been expected, were defeated; but they succeeded in stopping him for the day on which the battle took place… If Early had been put one day earlier he might have entered the capital before the arrival of the reinforcements I had sent.”

From the caption to the map:
Richmond and Petersburg were endangered, but the Southern leader, General Robert E. Lee, had sent General Early north to threaten Washington, D.C., at the least to force the Union commander at Richmond, Lieutenant General Ulysses S. Grant, to send soldiers back to defend the Capital.