Not the whole area, by far. The Crooked River National Grassland has "[…] a land area of 112,357 acre (175.56 sq mi, or 454.69 km²). It contains two National Wild and Scenic Rivers . . . "
Lemme see if I can find an overview of the place. Hang on, I'll be right back . . .
. . . I'm back. Boy, there is little that I can find.
GIS stuff here: http://www.fs.fed.us/r6/data-library/gis/ochoco/index.shtml – but that appears to be for the entire Ochoco National Forest, the printed maps for the forest show the CRNG in the upper left corner. It's not contiguous with the main body of the forest. The CRNG may not even be considered part of the Ochoco Nat'l Forest, they may have just added it to the map "because."
To put a rectangle around the area, I'd put the upper left corner at N44 45' W121 05', lower right corner at N44 35' W120 95' — these are eyeball estimates taken from pages 51 & 63 of the 2010 "Oregon Road and Recreation Atlas" by Benchmark Press.
The area is covered in much better detail in the map "Ochoco National Forest & Crooked River National Grassland" published by the USDA Forest Service & BLM.
I could scan the relevant part of the Forest Service paper map and p-mail it to you if it would help you find the actual boundaries of the Grassland.
See, that's my point: USFS (USDA) nat'l parks are not well-supported by online map resources. I think they want you to buy the paper maps.
The lack of online maps for the national forests totally frosts my pumpkin.
I spent this last week driving and hiking in and around the Melheur, Ochoco, and Deschutes Nat'l Forests, and was mainly out of range of a cell tower the whole time. I had to rely on paper maps (I don't mind, I grew up reading paper maps, but for crying out loud this is the 21st century!) and would have appreciated detailed maps cached in the iPhone.