Source: AMC
And for those outside of the US:
The Walking Dead is an American post-apocalyptic horror television series developed for television by Frank Darabont and based on the ongoing comic book series, The Walking Dead, by Robert Kirkman, Tony Moore and Charlie Adlard. The series centers on a small group of survivors led by Sheriff's Deputy Rick Grimes and his family.
The series premiered on October 31, 2010, and is broadcast on the cable television channel AMC in the United States.
The first season premiered to universal acclaim and was nominated for several awards, including the Best Television Series Drama at the 68th Golden Globe Awards. Based on its reception, AMC renewed the series for a second season of 13 episodes which premiered on October 16, 2011.
The pilot received 5.3 million viewers, making it the most-watched premiere episode of any AMC television series The first season finale received 6 million viewers, a series high; with 4 million viewers in the 18–49 demographic, making it the most watched basic cable series for the demographic.
In the United Kingdom, it premiered one week after it did in the United States, on November 5, 2010 on cable channel, FX. The premiere had 579,000 viewers, almost double for any other show on FX that week. The viewership dipped during the season then rose to 522,000 viewers for the final episode. The terrestrial premiere on Channel 5 on April 10, 2011, averaged 1.46 million viewers.