Piątnica was founded by Janusz from Zaborowo who built the first church there (1407).

The village has also a Neo-Gothic church (1931), which was destroyed during the Second World War and reconstructed after that.

There are also Russian forts from the 19th century and from the First World War in its vicinity.

During World War II, the forts played a crucial role during the Battle of Łomża.

One of Poland's largest dairy cooperatives is based in Piątnica.