The 1777 Encampment marker belongs to the First Middlebrook Encampment, where George Washington positioned the Continental Army from late May to early July. After victories at Trenton and Princeton, the Americans spent the winter around Morristown while British troops occupied New Brunswick and other New Jersey posts. Washington did not know whether General William Howe would move toward Philadelphia by land, attack his army, or support operations farther north, so he needed a secure observation point.

The Watchung Mountains north of Bound Brook offered a strong defensive position above the Raritan Valley. Steep approaches protected the army, while lookouts could observe British movement across the plain toward New Brunswick. The main force entered the area on May 28, and advance units occupied slopes facing the valley. Several thousand soldiers lived in tented brigade camps, with many reported sick or otherwise unfit for duty, reflecting the army's continuing shortages and health problems.

Howe attempted to draw Washington down from the heights into open country where the larger, better-trained British army could attack. British columns moved and withdrew across central New Jersey, while American detachments watched, skirmished, and avoided a general engagement. Washington refused the bait. The defensive value of Middlebrook lay precisely in allowing him to threaten British communications and respond to movement without gambling the army in an unfavorable battle.

Unable to force a decisive encounter, Howe eventually withdrew toward Staten Island and chose to move against Philadelphia by sea. That choice produced a lengthy voyage and delayed the campaign. Washington left Middlebrook on July 2 and shifted north before later marching to defend Philadelphia. The Continental Army returned to the broader Middlebrook region for a much longer winter cantonment in 1778–1779, so the two encampments are sometimes confused.

Tradition also associates Middlebrook with an early display of the new national flag after Congress adopted the Stars and Stripes on June 14, 1777. The precise circumstances are difficult to document, but a thirteen-star flag flies continuously at the Washington Camp Ground by congressional authorization. Portions of the landscape, including high ground and an earthen redoubt, preserve the strategic relationship between ridge and valley even as development has covered much of the camp.

The marker's dates distinguish this spring camp from the later cantonment. It commemorates a strategic success without a major battle: Washington preserved his army, denied Howe an easy land route, and used terrain to prolong the war. The site helps explain why encampments mattered as operational positions rather than mere places of rest. From these slopes, observation, restraint, and the credible threat of counterattack shaped British decisions across New Jersey.