This was something I've been thinking about recently:
Nearly every congressional district in the country has at least one urbanized area (or a significant portion of one) within its boundaries. For those that don't know, an urbanized area is defined by the US census as a densely-populated area with at least 50,000 residents - to some extent, this can represent the cutoff point between what most people would think of as urban and rural (50,000 people is fairly close to what most would consider a city). Thus, nearly all CDs are anchored by at least one "urban center". (You can find a list of urbanized areas here:
http://www2.census.gov/geo/ua/ua_st_list_ua.txt )
But there are also a few districts with little, or even no urbanized areas at all. The biggest that they have are fairly small cities (usually in the 10 to 20 thousand range). With no urban areas to unite or influence the districts, these districts are as close to "rural" as possible.
Here are a few examples that I can think of:
-MI-1 (Contains the UP and the northern LP, well to the north of any urban centers).
-MN-7 (Does contain a small urbanized population in the suburbs of Fargo and Grand Forks, but this makes up a very small part of the district's population.)
-KY-1 (Since Owensboro is not in the district, the only urbanized population is in a few suburbs of Clarksville, Tennessee).
-KY-5 (I honestly don't think this district has any urbanized area - not even a little).
-MS-1 (Pretty certain the only urbanized population resides in the southern Memphis suburbs in DeSoto County).
-OK-2 (Contains some Tulsa suburbs in Rogers county, and a very small urbanized population in some tiny suburbs of Fort Smith, Arkansas, but these make up less than 10 percent of the district's population.)
-Honorable mention: The old TN-4 (Which had a very small urbanized population - mainly from a hand that extended into Williamson County - and under a neutral map, would likely have virtually no urbanized population. The current TN-4 was drawn to pick up Murfreesboro, making it considerably more urban.)
Does anyone have any other examples?