Sausthorpe is a small village and civil parish in the East Lindsey district of Lincolnshire, England, 8 miles (13 km) east of Horncastle and 3 miles (4.8 km) north-west of Spilsby. It lies on the southern edge of the Lincolnshire Wolds – a designated Area of Outstanding Natural Beauty – in the valley of the River Lymn. Farming remains the dominant economic activity in the area. The population was 305 in the 2011 census and estimated at 306 in 2019.