Lamongan Regency is a regency of the East Java Province of Indonesia. It has a total land area of approximately 1,812.8 km2 (699.9 sq mi) or + 3.78% of the area of East Java Province. With a length of 47 km (29 mi) along the coastline, the sea area of Lamongan Regency is about 902.4 km2 (348.4 sq mi), if calculated to a distance of 12 miles (19 km) across the ocean surface. At the 2010 census it had a population of 1,179,059; the 2020 Census produced a total of 1,379,628 and the official estimate as at mid-2023 was 1,385,835. The regency seat is the town of Lamongan, situated on the Solo River which passes from west to east through the regency, effectively dividing it in two.