Fléchin is a commune in the Pas-de-Calais department in the Nord-Pas-de-Calais region of France.
A farming village situated 13 miles (21 km) south of Saint-Omer, at the D95E1 and D77 road junction.
Surrounded by the common Febvin-Palfart, Enquin-les-Mines and Laires, Fléchin is located 20 km northwest of the Bruay Buissière the largest city around.