The BIA office serves as the liaison with the Indian Health Service, various state, county and other federal and public agencies, and with the tribal organizations, committees, and tribal officials. The Agency consists of the following branches: real estate, probate, land operations, roads, social services, and facilities management.

The Lower Brule Agency is located at Lower Brule, South Dakota, and services the Lower Brule Sioux Tribe and Tribal Lands in Lyman and Stanley counties in central South Dakota. Lower Brule Law Enforcement Office covers the Lower Brule Sioux Tribal Lands. The Bureau of Indian Affairs - Office of Law Enforcement has overall responsibility of enforcement of Federal and Tribal Laws within the Lower Brule Sioux Tribal Lands.

Services provided to the Tribe are probate and estate, real estate, natural resources, fire management, tribal operations, self-determination, facilities management, and social services.

The Great Plains Regional office is responsible for the direction and oversight of Bureau responsibilities and activities in South Dakota, North Dakota, and Nebraska. The Office of the Regional Director provides program direction and supervision to 12 Agencies encompassing 16 federally recognized Tribes. Programs includes: tribal government, enrollment, claims, self-determination, housing improvement program, loan guaranty and interest subsidy program, land titles and records office, probate and estate services, real estate services, Indian land consolidation program, Division of Natural Resources, Human services (which includes general assistance, burial assistance, disaster assistance, emergency assistance, adult care assistance, and child assistance), Tribal transportation program, road maintenance, and Division of Environment, Safety, and Cultural Resources Managements.

911 emergency operators, adult detention, juvenile detention, and law enforcement services with jurisdiction within the exterior boundaries of the Cheyenne River Sioux Tribe.

The Yankton Sioux Tribe is located in the lower eastern part of Charles Mix County. The Tribe has approximately 11,594 members and approximately 4,600 member reside within the boundaries. Law enforcement covering Yankton Sioux Tribe.

Standing Rock Agency: formerly known and established in 1868 as Grand River Agency on the banks of the Grand River (South Dakota) and relocated upstream in 1874 and renamed Standing Rock Agency (Ft. Yates, North Dakota), is the Field Office for the Bureau of Indian Affairs providing Trust Services and Indian Services to the Standing Rock Sioux Tribe. Services include real estate, probate and estate, wildland fire management, administrative, social services, facilities management, and law enforcement services.

Major programs operated by the agency include: executive direction and administration, Real Property Management (Realty and Natural Resources), road maintenance, wildland fire, Human Services, probate, and transportation.

Rosebud Sioux Tribe Law Enforcement Services provides community policing services and criminal investigation services for over 22,000 community members; spanning an area of over 1.4 million acres.

Within the Flandreau Santee Sioux Tribe are the following services - Tribal Police Department - Law Enforcement Services (offers fingerprinting, background checks, and gun locks), social services, enrollment, tribal courts, child care, Dakota language, Department of Natural Resources, Education, Tribal Health Clinic, Counseling Center, Grace Moore Senior Center, Housing, and Wellness Center.

Sisseton-Wahpeton Tribal Police covers the Sisseton-Wahpeton Oyate of the Lake Traverse Tribal Lands.

The Bureau of Indian Affairs Pine Ridge Agency is located in Pine Ridge, South Dakota and provides services to the Oglala Sioux Tribe. Services include Real Estate Services (Leasing, Rights-of-Ways, and Acquisition & Disposition), fire management, social services, land operations, probate & estate services, facilities management, executive direction and administrative services.

Oglala Sioux Tribe Department of Public Safety provides Police and Dispatch services to the people on the Pine Ridge Tribal Lands.

Provides police services for the Yankton Sioux Tribe.

Protects the rights of the citizens within its jurisdiction to be free from criminal attacks, to be secure in their possessions and to live in peace. Year-round prescription drug take-back site.

The Sisseton Agency provides the following services on the Lake Travers Reservation: realty services, probate, social services, and road maintenance.