Cosmos

The smallest galaxy discovered so far is Segue 2, located adjacent to the Milky Way.

An excerpt from the article 25 facts about Cosmos

It is 114.000 light years away from us and is approaching at a speed of 40 km/s towards us. It is made up of about 1000 stars and has a diameter of 221.79 light years, so it is more than 9000 times smaller than IC 1101.