A Chapel St. Leonards landmark is Chapel Point, 1 mile (1.6 km) north from the centre of the village. It is a restored part of a major Second World War coastal defence line; the restoration included the Gun Structure and the Viewing Platform. In recent years Chapel Point has become a location for birdwatchers, being visited by migrating birds such as the Mediterranean Gull.
The name of the village derives from a chapel at Mumby dedicated to St Leonard; the village history is tied to that of Mumby, both at one time being part of the same ecclesiastical parish.
The village Anglican church, also dedicated to St Leonard, was rebuilt in 1572 after a flood, and again rebuilt in 1794 on a smaller scale. There was further rebuilding in 1866 and in 1901 when the church was lengthened and the red-tiled tower, unique in Lincolnshire, was added. In 1924 the chapel was again enlarged and lengthened, and a new east window and reredos added. The present church holds parish registers dating from 1665, although Bishop's transcripts go back as far as 1568.