In response to the growth of the System and a previous division into four regions of the Civilian Conservation Corps, the following regions were established in 1937::

Included ME, NH, VT, MA, CT, RI, NY, NJ, PA, OH, DE, MD, WV, VA, KY, NC, SC, TN, GA, AL, MS, LA, FL.

Included MI, WI, IN, IL, MN, IA, MO, ND, SD, NE; KS, MT (except Glacier) WY, CO (except Mesa Verde, Colorado NM, Black Canyon of the Gunnison, Great Sand Dunes, Hovenweep and Yucca House), UT (only Dinosaur).

Included AR, OK, TX, NM, AZ, CO (only Mesa Verde, Colorado NM, Black Canyon of the Gunnison, Great Sand Dunes, Hovenweep, and Yucca House) NV (only Boulder Dam Recreation Area and Lehman Caves), UT (only Rainbow Bridge, Natural Bridge, Arches).

Included CA, WA, ID, OR, NV (except Boulder Dam Recreation Area and Lehman Caves) UT, (except Rainbow Bridge, Natural Bridge, Arches and Dinosaur) MT (only Glacier), AK, HI.

A "Memorandum to all" went out to the field on April 25, 1940 which officially announced the four regions and their directors, although the regions had been in existence since 1937. The major purpose of this memo was probably to announce the "final" regional alignment, including the change mentioned in the next entry.

Glacier was moved from Region IV to Region II. Region III included all of Utah.

Region I was subdivided to create Region V:

Included AL, AR, FL, GA, KY IA MS, NC, SC, TN, VA (except Geogre Washington parkway, Lee Mansion, Prince William), WV

Included CO (except Mesa Verde, Great Sand Dunes, Colorado NM, Black Canyon of the Gunnison, Hovenweep, Yucca House), IA, KS, MN, MO, MT, NE, ND, SD, WY, UT (only Dinosaur).

Included AZ, NM, OK, TX, UT (except Dinosaur), CO (only Mesa Verde, Black Canyon of the Gunnison, Colorado NM, Hovenweep, Yucca House, Great Sand Dunes), NV (only Lake Mead).

Included CA, ID, NV (except Lake Mead), OR, WA, AK, HI.

Included CT, DE, IL, IN, ME, MD (except Suitland Parkway, Baltimore/Washington Parkway, Catoctin), MA, MI, NH, NJ, NY, OH, PA, RI, VT, WI.

National Capital Parks achieved regional status, but not the title.

National Capital Parks was made Region VI, 12/4/61.(From 1962 to 1969 it remained a Region. In 1970 it lost its regional status. From 1971 to the present, it has been a Region).

Numerical designations were dropped in favor of geographical ones:

In December, the Northwest District was created as a semi-autonomous unit of the Western Region.

National Capital Region became National Capital Parks (12/5/69)

The Northwest District of the Western Region became the Pacific Northwest Regions

Included AK, ID, WA, OR, CA (only Lava Beds).

In November, in response to the Administration's call for common regional boundaries, the NPS regions were realigned:

AL, FL, GA, KY, MS, NC, SC, TN, PR, VI, Cumberland Gap, Blue Ridge Pkwy.

CO, UT, AZ (only Glen Canyon and Pipe Springs), IA, KS, MO, MT, NE, ND, SD, WY

NM, OK, TX, AR, LA

CA (except Lava Beds), NV, AZ (except Glen Canyon and Pipe Springs), HI.

MN, WI, MI, IL, IN, OH, ME, NH, VT, MA, CT, RI, NY,

NJ, WV (except Harpers Ferry NHP), MD(except Suitland Parkway, Baltimore/Washington Parkway, George Washington Memorial Parkway, C & O Canal, Antietam, Harpers Ferry NHP, Catoctin, Fort Washington, Piscataway), PA, VA (except George Washington Memorial Parkway, Arlington House, Prince William, Blue Ridge Parkway, Cumberland Gap)

AK, ID, OR, WA, CA (only Lava Beds)

DC and areas excluded from MD and VA (except Blue Ridge Parkway and Cumberland Gap which were included in Southeast), (Harpers Ferry NHP administered by Harpers Ferry Center from 3/16/70 to 3/16/74).

In December, as part of a Servicewide reorganization, two new regions were created: Rocky Mountain out of the Midwest Region and North Atlantic out of the Northeast Region which had its name changed to Mid-Atlantic. Regional boundaries were realigned:

KY, TN, NC, SC, GA, MS, AL, FL, PR, VI, Blue Ridge Parkway and Cumberland Gap NM.

NE, KS, IA, MO, MN, WI, MI, IL, IN, OH.

NM, OK, TX, AR, LA

In 1974 added AZ (only Navajo, Canyon De Chelly, Wupatki, Sunset Crater and Hubbell Trading Post).

CA (except Lava Beds), NV, HI, AZ (except Navajo, Canyon De Chelly, Wupatki, Sunset Crater, and Hubbell Trading Post (1974))

PA, WV (except Harpers Ferry), DE, VA (except Manassas, Wolf Trap, Prince William Forest), MD (except C & O Canal, Catoctin, Antietam, Baltimore/Washington Parkway, Fort Washington, Greenbelt, Suitland Parkway, George Washington Memorial Parkway).

DC and parks listed above as excluded from MD, WV and VA.

AK, WA, ID, OR, CA (only Lava Beds)

MT, WY, CO, ND, SD, UT, AZ (only Pipe Springs and Glen Canyon)

MA, VT, NH, ME, NY, NJ (except Delaware Water Gap NRA), CT, RI

National Capital Parks became National Capital Region 10/21/76.

Lava Beds moved to Western Region.

Alaska Area Office mad a part of the Field Directorate.

Alaska Region created 12/3/80

Effective 5/31/95, National Park Service restructuring brought about major changes. Regions were combined and renamed Field Areas and 16 System Support Offices were set up:

Southeast became Southeast Field Area with the following System Support Offices (SSO):

North Atlantic and Mid-Atlantic were combined into a new Northeast Field Area with the following SSOs:

Alaska became Alaska Field Area with the Alaska SSO

Western and Pacific Northwest were combined into a new Pacific West Field Area with the following SSOs:

Southwest and Rocky Mountain were combined into a new Intermountain Field Area with the following SSOs:

Midwest became Midwest Field Area with the following SSOs:

National Capital became National Capital Field Area with a National Capital SSO

Atlantic Coast SSO became Atlantic SSO

Columbia Cascade SSO became Columbia Cascades SSO

Pacific Great/Basin SSO became Pacific Great Basin SSO

The designation "Field Area" was changed back to "Region" and System Support Offices were retitled "Support Office."

In the Midwest Region, the Great Lakes and Great Plains SSOs were combined into the Midwest SO

In the Northeast Region, the Allegheny, Chesapeake and New England SSOs were restructured into the Boston and Philadelphia SOs

In the Southeast Region, the Appalachian, Atlantic and Gulf Coast SSOs were combined into the Southeast SO

In the Intermountain Region, the Colorado Plateau, Southwest and Rocky Mountain SOs were restructured into the Denver and Santa Fe SOs