I would think there would be a few in the reservoirs to the south east of Pincher that would have a few.  There are some in the oldman river as well that would be fun to catch on a fly.

Never fished the system for pike just the upper reaches for cutties but if it were me I would be looking at the damn. Pike are a pretty predictable fish especially in the spring. I would Google map the damn, seek out some of the long bays close to any stream and concentrate on any long shallow bays or reaches. If they are in there they will be in the shallow sandy spots warming up and getting some sun.

If it were me I would look at some of the reservoirs as weste suggested most of them are loaded with pike. Same method would apply,, shallow bays in 3 feet of water will be the most productive early in the season.

Again, Google maps is your best friend, just look around your area, if it's a reservoir fed by any of the major canal systems it will have pike in it.

Pike on the fly are a blast, i just got into it last spring. Purchased a 9 weight fly rod and gear and hit them around home last spring in the shallows. Let me tell you,, when a 12# pike nails you on a fly rod in 3' of water you know you have a fish on,, it's a rush. My boys and I are looking forward to it again this spring.

Where does a guy start running into pike on the oldman river? I read a few things about pike only being in certain parts of the river

try just down river of the dam but like SouthernGuy states, the reservoirs are always a good bet.