In the U.S., what government dept. regulates the cable companies?

Answer 1

For the most part, it's the state's public utilities commission or equivalent.  

The FCC does have broad regulations.  

Answer 2

Federal Communications Commission

Answer 3

There are several departments that have some oversight, but the main one is the Federal Communications Commission (FCC).  However, for most issues regarding how any particular cable company does business, the regulation comes mostly from the fact that the cable company is granted a license to operate in a particular region of each state where it does business.  This is so the poles don't get covered with five or more different sets of cables as Cox and Verizon and Comcast and AT&T all compete for everyone's business.  Such arrangements are overseen by state boards in the same way that electric, gas, and water monopolies are.  So the state regulators can be more important than the federal ones, in many cases.

Answer 4

F.C.C., Federal Communications Commission ......................