Why are jelly donuts usually raspberry flavored Why are jelly donuts filled with raspberry flavored jelly unless specified otherwise.  There are lemon filled, strawberry filled, etc but if you just ask for a "jelly donut" it will be raspberry filled.
I think this might actually be a regional thing. In my area, we're more likely to get blueberry or apple jelly doughnuts. It's probably got to do with whatever fruit is cheapest to use in large quantities for the location where the doughnuts are being made.