Colneis is a hundred of Suffolk, consisting of 16,712 acres (67.63 km2).
Running from the south-east outskirts of Ipswich to the North Sea coast, the hundred is made up of the land between the estuaries of the rivers Orwell and Deben. It is one of the smallest in Suffolk, being only about four miles (6 km) wide and ten miles (16 km) long between its border with Carlford Hundred and the cliffs at Felixstowe. It lies within the Colneis Deanery, in the Archdeaconry of Suffolk.
Listed as Colneyse in the Domesday Book, the origin of the name is not known for sure, though the suffix -ness, meaning "headland" seems probable. The col may be the old name of the Deben before its renaming after Debenham.
The name survives as that of a Junior School in Felixstowe.
Colneis Hundred consists of the following 10 parishes:
Coordinates: 52°00′N 1°18′E / 52.0°N 1.3°E