Via Farm Policy, Senator Grassley has written USDA about the possible closures of FSA offices in Iowa. He goes so far as to challenge the 20 mile distance, pointing out that a couple of the offices are actually at least 23 miles away from another FSA office by road.
In a way this sort of letter is the obverse of earmarks; it's the elected representative using his local knowledge, or rather channeling the local knowledge of his constituents, to affect the decision-making of a bureaucracy. I think we'd all agree this is useful, even though some of us may oppose earmarks.
On a lighter note, I was remembering Roy "T" Cozart, an official in ASCS in the 1970's/80's. He was, I believe, CED of Deaf Smith County, Texas (pronounced "deef" and named after the scout first into the Alamo after the killing stopped). Maybe it was that county, maybe another, but he delighted in mockery and one thing he'd mock was Easterners and the way he'd mock was to describe how long it would take to drive his county, hours and hours at least as I remember it.
Maybe he was pulling my leg, because with the magic of Wikipedia I can find that Deaf Smith county is just about 1500 square miles, meaning it's a rectangle roughly 30 by 50 miles. In the Texas panhandle it wouldn't have taken long to drive, so maybe Roy was reminiscing about his days as district director in middle Texas. For comparison, Linn County in Iowa is about 750 square miles.
Sen. Grassley's constituents face a round trip drive of 25 miles to the FSA office, maybe 35-40 minutes assuming Iowa roads are straight. In Texas one assumes the distance would be double or triple that. And if you want to talk about Montana: the counties mostly range from 2000 to 5000 square miles.
What's my point? The distance parameter is arbitrary. No corporation, no Walmart or Subway, would allocate their stores the way the US government allocates its offices.