The Kleiner Bornhorster See (Little Bornhorst Lake) covers 20 hectares and has a circumference of approximately two kilometers. It is one of the larger lakes in the Oldenburg urban area and the surrounding area. It is almost circular in shape and measures just under 500 meters north-south, with the east and west shores up to 600 meters apart. To the north, a small peninsula juts out into the lake, forming a kind of lake angle. The lake lies 0 meters above sea level. On the west shore, there is a sandy beach approximately 150 meters long and up to 40 meters wide, as well as numerous sunbathing areas. The Kleiner Bornhorster See is an official swimming lake monitored by the DLRG (German Lifesaving Association).
400 meters south of it lies the Grosser Bornhorster See, which is more than twice as large. The A29 federal highway runs between the Kleiner Bornhorster See and Groß Bornhorst or Etzhorn, just 200 meters from the west shore. The lake owes its existence to the expressway ring around Oldenburg: the soil taken from the lake was needed to build the ramp to the Hunte high bridge as well as the embankments of the A 293 and the northern bypass.