Here is a neighboring Maryland district that dips inside hollowed out area of the other district in the south but wraps around that other district in the north.
Almost every district in Maryland gets a slice of Baltimore or borders DC.
7 of 8 MD districts have a Democrat in the House.
But at least a clear majority of Maryland votes are for Democrats.
In some states Republicans have been able to elect a majority Republican Congressman even with more votes going to Democrats.
As Trolly said, they will draw all of the Democrats into one district.
Ohio votes about 50/50 but 75% of their elected House members are Republican.