Contact hardwood sawmills. You may have to use the internet search features to find them near you, but if you talk to lumberyard owners, around you, they generally know where the closest mills are located, and can give you some good contacts to call.
We have lots of hickory growing around this part of Illinois and Indiana, in the Wabash river valley. Ramrods require long straight grained trees, and you find them growing up out of the bottom of steep ravines, in deep forest, where the tree grows very tall to reach sunlight with its leaves, and the land and forestsprotects the tree from being rotated, or "twisted" by prevailing winds.
Cut these in the winter when the sap has run down out of the branches, and all the leaves have fallen off, so that the grain is tight, and strong. Wood cut in the winter makes the best tool handles, and the best ramrods. Always ask mill operators when the hickory stave( split) they are trying to sell you was cut. I first heard about this on the Woodwright shop TV show, on PBS, then confirmed it talking to some loggers I had as clients, then talked to some forestry majors, and finally talked to some expert axe handle makers.
Then I happened to meet Dick Greensides from Pecatonica River at his booth at Friendship when I was looking for a couple of rods for club members who could not make the trip over. Dick mentioned the same thing when I was looking at the grain and cast of his wooden ramrod blanks.