Here's a detailed breakdown of the Pre-partition Punjab districts based on demographics per religion, population density and how the border was eventually drawn to divide the Punjab province. Interesting point to note that the area around Amritsar was pre-dominantly Muslim but the British wanted to give Amritsar stratgic buffer otherwise it would have been surrounded by Pakistan on three sides.

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http://pakgeotagging.blogspot.com/2014/10/partition-of-punjab-in-1947.html