Bernie Sanders the most liked, Mitch McConnell the least, and he is the majority leader.
This can happen only in America.
Surprisingly, not all Senators with top ten approval ratings are that well known nationally. The least popular OTOH which includes Mitch (#100), McCain (#99), Graham (#98) are quite well known nationally with five Democrats and five Repubs in the bottom ten.
https://morningconsult.com/senate-rankings-april-2017/