Trejgle is a settlement in the administrative district of Gmina Krynki, within Sokółka County, Podlaskie Voivodeship, in north-eastern Poland, close to the border with Belarus. It lies approximately 5 kilometres (3 mi) south of Krynki, 28 km (17 mi) south-east of Sokółka, and 44 km (27 mi) east of the regional capital Białystok. The climate is cold and temperate.