Offering protection to the Thames River was a fort built and named after Governor Matthew Griswold of Lyme--Fort Griswold. A relatively impressive fort built in european star style with a "V" shape works created to protect the entry. This works was created to simply protect the fort´s doors from canonade. Barracks for up to 300 men were also built. Walls built of stone and earth nearly 9 feet tall Fort Griswold was an impressive site especially for potential raiders coming up the river. Its cannon could reach ships in the Long Island sound and was built high enough above any invading landforce coming from the river to give it the advantage. However as early as 1776 the fort almost new was already in disrepair as noted by several men who manned the fort. Once Colonel Ledyard, Capt.Shapely and Coit of New London noticed this funds were demanded and the fort "somewhat" repaired.
Also supporting Groton Bank were a series of Sea Coast Guard posts that ran from Noank and Portersville (Mystic) to Gales Ferry, again manned by 5-20 men they were designed to give warning of potential danger and to eventually limit the smugling of goods to and from Long Island a Tory stronghold. These posts also were located at Waterford (modern day Waterford Beach), on Black Point in the Niantic part of East Lyme as well as from time to time at Giant´s Neck and toward Lyme first society (Old Lyme).
Protecting from the New London side was a newly built Ft. Trumbull (named for the governor of Connecticut). It faced the waterfront but was not defendable from the western land side proving to be a weakness to be exploited. Also Ft.Folly or Nonesense was located about half way to the downtown area of New London from Ft. Trumbull and was a simple earthen works with a canon. At the bottom of "Main Street" (State) was a small battery with a canon as well.
Another defensive position was at Winthrop Cove near the modern day Gold Star Bridge to protect an important wharf and shipyard owned by Guy Richards.
Although several alarms were sounded during the war and other than the odd "probing" effort usually by Long Island Tories to steal cattle and supplies,.trade with local tories the area was spared the wrath of war. Sir Henry Clinton, commander of all British forces in America called the Thames River area "The Den of Serpents" as the various privateers that came out of New London took hundreds of prizes and there were was little the King's Navy and Army could do to prevent it.
A series of signals were established to notify the countryside of:
2 Consecutive Shots by Cannon -Alarm for Help - Call to Arms
3 Consecutive Shots by Cannon -A prize has been taken (Privateer) & has arrived in New London
In addition each of the guard posts would use fires to signal the call to arms.