New East Prussia (German Neu-Ostpreussen) was the easternmost province of the Kingdom of Prussia between 1795 and 1807, created from areas acquired during the third Partition of Poland, with Warsaw as a capital. The area of the province was less then 55,000 km² and population was approximately 1 million inhabitants.

The province ceased to exist when Napoleon taken it in 1807, and the territory became a part of the Duchy of Warsaw, except the Bialystok district which was ceded to Russia.

In 1806, New East Prussia had 914,610 inhabitants, and was divided into two "departments":

Bialystok ("Departement der Kriegs- und Domainen-Kammer zu Bialystok") included the counties ("Kreise") of

• Łomża
• Drohiczyn
• Bielsk
• Supraśl
• Białystok
• Bobrz
• Dombrowa (Polish: Dabrowa Bialostocka)
• Wygry (Polish: Wigry )
• Góra Kalwaria
• Mariampol

Plozk ("Departement der Kriegs- und Domainen-Kammer zu Plozk") included the counties ("Kreise") of:

• Płock
• Wyszogród
• Lipno
• Mława
• Przasnik
• Pułtusk
• Ostrołęka