Quantico is still in the UCAS.
Yes, the maps are incorrect. The UCAS/CAS border is the Rappahannock River.
Yes, there is a North Virginia. Even if there wasn't, Langley and the Pentagon (and every other LE/Intel agency) are headquartered well within the FDC, since the FDC is comprised of Washington and the following counties: Arlington, Fairfax, Montgomery, Howard, Prince Georges.
Spy Games doesn't have much about the FBI except for its national security (counterintel, counterterror, etc.) section.
I have compiled a list of every UCAS federal agency for the DeeCee section of Conspiracy Theories. It's considerably smaller than RL.
Anyway, the national police in Salish are the Rangers, which is a paramilitary police force that used to also serve as its military until the war with Tsimshian. There are also separate Border and Coast Guards. In Sioux it's the Sioux National Police. In PCC it's the Security Force, which is both the police (Civil) and military (Defense). Tír Tairngire has the Peace Force. CAS has the Department of Domestic Investigations, (Department is the CAS term for agencies. UCAS-eqv. depts. are Bureaus), which is a catchall federal law enforcement agency. However, the CAS Secret Service exists as a sub-agency of the DDI to perform executive protection.