Pittsburgh has channels positioned in quite a few places on Comcast.
In Westmoreland County, KDKA-2 (CBS-owned) is on Channel 2, WTAE-4 (Hearst, ABC) on Channel 3, WINP-16 (ION-owned) on Channel 4, WPGH-53 (Sinclair, FOX) on Channel 7, WQED-13 (WQED, PBS) on Channel 9, WPMY-22 (Sinclair, MyTV) on Channel 10 (this is a common placing for My-TV Pittsburgh on quite a few systems), WPCB-40 (Cornerstone, religious) on Channel 11, WPXI-11 (Cox, NBC) on Channel 12 and WPCW-19 (CBS-owned, CW) on Channel 15.
In Monroeville, on a former Adelphia system, WINP-16 uses Channel 16, but WPCW is on 2, KDKA 3, WTAE 5, WPGH 6, WPCB 9, WPMY 10, WPXI 12 and WQED 14.
In Pittsburgh proper, it's WINP 4, WPCB 5, KDKA 6, WPGH 7, WTAE 8, WQED 9, WPMY 10, WPXI 12 and WPCW 15.
Of course, one also has to consider the digital lineup where there is some confusion of another sort. WPCW uses RF channel 11, WPXI's old analog position. WBGN, a regional independent not carried by Comcast, uses RF 16, WINP/WQEX's former analog slot, but is seen on digital channel 59 in Allegheny County.
WQED-13 has its old analog 13 position for digital broadcasting.
On FiOS, the lineup is KDKA-2 on 2, WPCW-19 on 3, WTAE-4 on 4, WPCB-40 on 5, WPGH-53 on 7, Pittsburgh Cable News Channel (WPXI's round-the-clock news outlet) on 9 (Comcast usually puts it around Channel 35), WPMY-22 on 10, WPXI-11 on 11, WQED-13 on 13 and WBGN on 22.