The earliest that my house had cable was in April of 1981, with United Cable here in New Britain, CT. It was a wired brown box with 12 click buttons on three levels, along with a fine tuning dial on the right side (made by Jerrold). The top row was for channels 2 to 13, middle was 14 to 25 and the third was for 26 to 37. HBO was on 14, The Movie Channel on 15 and Escapade (adult) was on 16 (we had The Movie Channel for a while). Those three channels were switched from something on the telephone pole outside. We still had that old brown box in our possession until the mid-90s. Analog customers could get HBO on cable channel 14 until as late as 2009! (I subscribed to it and had a converter in my bedroom. Since it was "open" for my floor, the second TV was able to get HBO with no box!
As for other early cable here, I seem to remember my grandparents having it in their apartment (same city as me) as early as 1977-78. Outside of the few locals, we received WWOR-TV, WPIX-TV and WSBK-TV. I think we even received channel 5 from New York when they were still independent WNEW-TV! By 1989, on my second go-around with cable, channel 5 was long gone, with WWOR, WPIX and WSBK still showing up (WPIX was removed on July 1, 1990, due to Syndex).