Posen District was the southern of two administrative districts (German: Regierungsbezirk, Polish:Rejencja, ) of the Province of Posen (1849-1918) by the Prussian administration and its predecessor the semi-autonomous Grand Duchy of Poznan (1815-1849).

It was bordered on the north by the Bromberg district, to the west by Brandenburg, to the south by Silesia and to the east by Congress Poland.

The Posen district was inhabited mainly by Poles and had a smaller percentage of German settlers, and was therefore less Protestant.

Divisions

Note: Prussian provinces were subdivided into units called "Kreise" (singular "Kreis", abbreviated "Kr.", English "circle"), which were similar to large counties in US terms. Cities would have their own "Stadtkreis" (English: "municipal county") and the surrounding rural area would be named for the city, but referred to as a "Landkreis" (English: "rural county"). In the case of Posen, the Landkreis was split into two: Landkreis Posen West, and Landkreis Posen East. The district was originally divided into 16 larger Kreise, which were later divided into the final 27 Kreise, the larger ones spinning off smaller units.

Data is from Prussian censuses, during a period state-sponsored germanization, and includes military garrisons. It is commonly critisized for lack of authenticity.

Kreis ("County")	Polish name	1905 Pop	Polish	German	Jewish	Origin
City of Posen	Poznań		55%
Adelnau	Odolanów		90%	10%		Ostrowo
Birnbaum	Międzychód		51%	49%
Bomst	Babimost		49%	51%
Fraustadt	Wschowa		27%	73%
Gostyn	Gostyń		87%	13%		Kröben
Grätz	Grodzisk		82%	18%		Buk
Jarotschin	Jarocin		83%	17%		Pleschen
Kempen	Kępno		84%	16%		Schildberg
Koschmin	Koźmin		83%	17%		Krotoschin
Kosten	Kościan		89%	11%
Krotoschin	Krotoszyn		70%	30%
Lissa	Leszno		36%	64%		Fraustadt
Meseritz	Międzyrzecz		20%	80%
Neutomischel	Nowy Tomyśl		51%	49%		Buk
Obornik	Oborniki		61%	39%
Ostrowo	Ostrów		80%	20%
Pleschen	Pleszew		85%	15%
Posen Ost	Poznań		72%	28%		Posen
Posen West	Poznań		87%	13%		Posen
Rawitsch	Rawicz		55%	45%		Kröben
Samter	Szamotuły		73%	27%
Schildberg	Ostrzeszów		90%	10%
Schmiegel	Śmigiel		82%	18%		Kosten
Schrimm	Śrem		82%	18%
Schroda	Środa		88%	12%
Schwerin	Skwierzyna		5%	95%		Birnbaum
Wreschen	Września		84%	16%