While working in the Des Moines, IA area I logged a few active federal frequencies.
165.2875, N650 - BATFE NET 1
167.8625, CSQ - VAMC Paging (Nationwide assignment)
170.8000, N293
172.9000, N001 - TSA at Des Moines International Airport
407.8375, N293 - VA Medical Center Police
416.1375, N482 - US Postal Inspectors, input to 407.1375 (GREEN Repeater)
419.0375 - Sounded like TRBO digital mode
There also appears to be quite a few channels at a major Postal Service sorting & bulk mail center:
406.3750, D065
407.3375, 103.5 pl
408.0000, 67.0 pl
409.7375, 114.8 pl
410.2000, D065
414.7250, D306
The busiest appear to the from the Iowa Air National Guard base at the Des Moines airport (KDSM). Since my last visit to the area, the frequencies have gone from analog to P25 with full time encryption! Here is what was found:
163.4625, N300 - Base Security
163.4875
163.5125, N200 - Base Fire & Crash Response
163.5375, N850
163.5875, N100 - Civil Engineering
165.0375, N450
165.1125, NA00 - POL Trucks
165.1375
165.1625
173.4125, N350
173.4375, N250 - Munitions
173.5375, N400 - Maintenance
173.5625