As of 7 a.m. MT, Democrats control both houses of the legislature in 23 states; Republicans in 15, and nine are split. Final counts aren't available yet for three chambers in two states: the Montana House and Senate and the Pennsylvania House. This adds up to 49 states because Nebraska's legislature is nonpartisan..
Before the election, Republicans controlled 20 state legislatures; Democrats 19, and 10 were split.
I'll round up the governorships and the referendum results some time today.