MYSTERY FREQUENCY - 168.2250 MHz

I recently saw a report of activity noted on 168.2250 MHz, P25 with a NAC of N001 during an Executive Branch Secret Service motorcade. 

I have not logged that frequency as associated with the Secret Service or White House Communications  Agency before. But I have logged it on previous visits to New York City (FBI) and Pittsburgh (FBI), Nashville, TN (unknown with a NAC of N555) and around the Washington, DC area, where it was in analog with a PL tone of 151.4. 

My records have this frequency assigned to multiple federal agencies, including:

Air Force

Army

Bureau of Land Management

Department of Energy

Justice Department - FBI

US Fish and Wildlife

US Geological Survey

Interior Department (Nationwide)

National Park Service

US Post Office

State Department

Anyone hearing this frequency near you?

MYSTERY FREQUENCY - 406.2875 MHz

I have had reports over several years of activity noted on 406.2875 MHz. My records did not have this assigned to any specific federal agency, but monitoring notes from various locations do record some activity on this frequency.  

Treasury/IRS Philadelphia, PA DMR

Federal Bureau of Prisons, Butner NC - part of the prison trunked system

Florida - Unknown location using DMR, heard in Orlando

Texas - Unknown location using DMR, heard in San Antonio 

Houston, TX - Heard over several years in analog using DCS 205, possible National Guard 

Kansas City, MO - Unknown agency using P25 with a NAC of N293 

Anyone else hearing activity on this frequency?