On my recent travels through Arizona, I spotted a Bureau of Land Management (BLM) Law Enforcement vehicle that had a large SATCOM antenna on the roof. There was also what appeared to be a multi-band land mobile radio antenna as well.
The large, platter shaped antenna is on the left side, over the drivers head. It is labeled with a number of warning emblems, probably telling you to not touch the antenna while in use.
I did not know that BLM had satellite capabilities, but it makes sense as they often operate in very remote areas, many miles from cell sites.
This is an additional agency that has been confirmed to have access to satellite voice and data communications. This list includes other Department of the Interior agencies, such as US Geological Survey, Bureau of Indian Affairs (BIA), FEMA, Customs and Border Protection (CBP), the Army Corps of Engineers and Health & Human Services.
There are likely more agencies that can use mobile satellite gear. The NIFOG does list some federal interoperability channels/networks that are available on satellite.