Established as a beacon at the 'Harbor's Mouth', as early as the late
1730s, the land where the Thames River meets Long Island Sound was
purchased in 1759 for the construction of New London Harbor Light,
also called the Pequot Light, in the reign of King George II. In 1761,
with money raised by selling lottery tickets, a 64-foot stone tower
with a lantern was erected at the west side of the harbor entrance.
The current octagonal tower, designed by Abisha Woodward, was
constructed of brownstone in 1801. New London Harbor Light was one of
the earliest American lighthouses with a flashing light. The revolving
eclipser gave it a distinct characteristic so it couldn't be confused
with the lights of nearby houses.
(http://www.nlmaritimesociety.org/NL-Harbor-Light.html)