Odsey was a judicial and taxation subdivision (a "hundred") of Hertfordshire, in the northeast of the county, that existed from the 10th to the 19th century.
It comprised the following parishes: Ardeley, Ashwell, Broadfield, Bygrave, Caldecote, Clothall, Cottered, Hinxworth, Kelshall, Newnham, Radwell, Reed, Royston, Rushden, Sandon, Therfield and Wallington. Newnham was transferred to Cashio Hundred some time between 1086 and 1286.[1]
The hundred appears to have been named after Odsey Grange, part of the parish of Guilden Morden, Cambridgeshire, indicating that the hundred originally included additional territory to the north.[2]