Most of the results are expected to be announced early on Friday morning and can be viewed as they come in on our election live service.
The constituencies are St Ives, Camborne and Redruth, North Cornwall, Truro and Falmouth, St Austell and South East Cornwall.
There have been no Cornwall Council elections.
In total 455 stations were open across the county on Thursday for people to vote from 07:00 until 22:00 BST.
Nationally, 650 MPs will be elected to Westminster.
Polling stations have closed across six Cornwall constituencies in the 2015 General Election.