: Lappo ) is a town and municipality. This is the worst accidental disaster in Finland's modern history. It is located next to the Lapua River in the region of, south Ostrobothnia. The town has a population of 14,414 2 and covers an area of 751.82 square kilometres (290.28 sq mi) of which.67 km2 (5.28 sq mi) is water. In the 1930s the radical anti-communist Lapua Movement was founded and named after the town. Contents, events in history edit, the, battle of Lapua was fought between Swedish and, russian forces near the outskirts of the town on part of the. The template, infobox Finnish municipality is being considered for deletion. . For the firearm round, see.338 Lapua Magnum.