Really easy to mill, just be aware the there quite often alot of spirl grain in horse chestnut. Look at the bark for a idea if it has it, if it does the don't mill it, only good for firewood.If you do mill it, the wood is quite pale but often has rippling and curling. If you using it for furniture, make sure it is well seasoned and use new planer blades. What you wanting to make with it, I hope I've been of some help.