Although the county contained a number of parliamentary boroughs, each of which elected one or two MPs in its own right for parts of the period when Northamptonshire was a constituency, these areas were not excluded from the county constituency.
Owning freehold property of the required value, within such boroughs, could confer a vote at the county election.
(After 1832, only non-resident owners of forty shilling freeholds situated in borough seats could qualify for a county vote on the basis of that property.)
Constituency created (1290) As there were sometimes significant gaps between Parliaments, the dates of first assembly and dissolution are given for those up to 1640.
Where the name of the member has not yet been ascertained or is not recorded in a surviving document, the entry unknown is entered in the table.