Some secondary sources say he died in MD, some say in DC; I haven't found documentation either way.

Our subject's granddaughter disputes that she had given name, "Anne," although all other secondary sources give her that name.
Some secondary sources say she died in MD, some say in DC; I haven't found documentation either way.

1.  LDS.  Family Search: Internet Genealogy Service: Pedigree Resource File (index to CDs, online at FamilySearch.org).

Oscar John CARRICO Birth: 20 Mar 1895, Macomber, Preston, West Virginia Death: 21 Sep 1961, Arlington, Virginia Father: Arthur Wellington CARRICO; Mother: Mary Florence FRETWELL Marriage: 20 Oct 1920 Wife: Marie Viola WATKINS Birth: 21 Feb 1899, Cumberland, Allegany, Maryland Source: Eric FRETWELL

John Pringle WATKINS Birth: 28 Sep 1871, Piedmont, Mineral, West Virginia Death: 4 Mar 1923, Cumberland, Allegany, Maryland Marriage: 1 Jan 1896, Preston, West Virginia Spouse: Bridget Mary BURKE Birth: 23 Jan 1872, Preston, West Virginia Death: 12 Jul 1953, Moreno Valley, Riverside, California Father: Patrick BURKE (c1839-1908); Mother: Honoria SAMON (c1836-1906) Children: 1. Annie Marie Viola WATKINS Birth: 21 Feb 1899, Cumberland, Allegany, Maryland Death: 3 Sep 1990, Washington, D.C. Spouse: Oscar John CARRICO et al. Source: Eric FRETWELL

Email from granddaughter disputes that she had given name, "Annie."

2.  1900 Census Every-Name-Index/Images (online at Ancestry.com):  John O. CARRICO (æ 5, b. Mar 1895, WV) is living in Reno Dist., Preston Co., WV, with his parents (q.v.).  Maria WATKINS (æ 1, b. Feb 1899, MD) is living in Cumberland, Allegany Co., MD (p. 110A), with her parents, John WATKINS (æ 26, b. Sep 1873, WV) & Bridget (æ 26, b. Dec 1873, WV).

3.  1910 Census Every-Name-Index/Images (online at Ancestry.com):  Oscar CARRICO (æ 15, b. WV) is living in Reno Dist., Preston Co., WV, with his parents (q.v.).  Marie WATKINS (æ 11, b. MD) is living in Cumberland, Allegany Co., MD (p. 229B), with her parents, John K. WATKINS (æ 37, b. WV), & Bridgett (æ 35, b. WV), plus siblings.

4a.  1920 Census Every-Name-Index/Images (online at Ancestry.com, Image #13 of 26):  Hotel, East Washington Street, Terra Alta Town, Portland Dist., Preston Co., WV, Roll T625_1969, p 178A, SN 7A, SD 2, ED 139, enumerated 8 Jan 1920, official enumeration date 1 Jan 1920 (extracted by Diana Gale Matthiesen):¤•

1920:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
2	3	4	5	6	9	10	11	12	17	18	19	21	23	25	26	27	28
X	145	156	Carrico Oscar	boarder	M	W	24	S	Y	Y	WV	WV	WV	Y	Car inspector	Railroad	W

One of many in a boarding house.

4b.  1920 Census Every-Name-Index/Images (online at Ancestry.com):  Marie WATKINS (æ 21, b. MD) is living in Cumberland (Ward 6), South Cumberland Twp., Allegheny [Allegany] Co., MD (p. 272B), with her parents, John WATKINS (æ 48, b. WV) & Bridget (æ 47, b. WV), plus siblings.

5.  1930 Census Every-Name-Index/Images (online at Ancestry.com, Image #43 of 88):  ?100 Thirteenth St. N.E., Washington (Precinct 12), DC, Roll 303 (Book 1), p. 59A, SN 22A, ED 356, SD 1, enumerated 10 Apr 1930, official enumeration date 1 Apr 1930 (extracted by Diana Gale Matthiesen):¤•

1930:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	24	25	26	27	28	30	31
*	?100	301	344	Carrico Oscar	Head	R	27.50	R	N	M	W	32	M	25	N	Y	WV	WV	WV	Y	Salesman	Oil Company	W	Y	Y	WW
				_______ Marie V	Wife					F	W	31	M	24	N	Y	MD	MD	MD	Y	None
				_______ William J	Son					M	W	8	S		Y		MD	WV	MD		None
*Thirteenth St N E

6.  1940 Census Every-Name-Index/Images (online at Ancestry.com, Image #4 of 60):  Washington, DC, Roll T627_560, p. 457B, SN 2B, SD 1, ED 1-225, enumerated 3 Apr 1940, official enumeration date 1 Apr 1940 (extracted by Diana Gale Matthiesen):¤•

1940:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean.
LOC		HOUSEHOLD				NAME	RELATION		PERSONAL				EDUCATION			BIRTHPLACE		CIT	RESIDENCE in 1935					EMPLOYMENT STATUS															FS
1	2	3	4	5	6	7	8		9	10	11	12	13	14		15		16	17	18	19	20		21	22	23	24	25		26	27	28	29	30		31	32	33	34
*	5235	44	0	7000		Carrico Oscar	Head		M	W	44	M	N	H4		West Virginia			Same House					Y	-	-	-	-		40		Clerk	Social ??? Board	PW		50	1440	N
						_______ Marie	Wife		F	W	40	M	N	H4		Maryland			Same House					N	N	N	N	H
						_______ William	Son		M	W	18	S	Y	H3		Maryland			Same House					N	N	N	N	S
*Fifth Street

7.  SSDI:  Social Security Death Index (online at Ancestry.com):

Name	SSN	Last Residence	Birth	Death	Issued	Comment
Marie V. Carrico	577-26-4937		21 Feb 1899	3 Sep 1990	DC bef. 1951	No
John W. Carrico	577-12-0375	Stuart, Martin, Florida 34996	28 Aug 1921	7 Sep 2002	DC bef. 1951	No
Arlyne E. Carrico		Stuart, Martin, Florida 34996	5 Jul 1921	14 May 2007	DC bef. 1951	No

8.  National Cemetery Administration.  Nationwide Gravesite Locator: U.S. Veterans Cemeteries, ca. 1800-2004 (online at Ancestry.com):

Name:	Oscar John Carrico
Service Info:	2D LTINF RES SGT CO B 137 MG BN 38 DIV USE
Birth | Death Date:	20 Mar 1895 | 21 Sep 1961
Interment Date:	26 Sep 1961
Cemetery:	Arlington National Cemetery
Cemetery Address:	c/o Director Arlington, VA 22211
Burial at:	Section 47 Site 973

9.  Find-a-Grave: Entries (online at findagrave.com):

Except for the tombstone images and occasional mention of a death certificate, this database consists of undocumented patron submissions, so caveat emptor.
Name:	Oscar John Carrico	Marie Viola Carrico	John William Carrico	Arlyne E. Carrico-Butterworth
Birth:	Mar. 20, 1895	Feb. 21, 1899	Aug. 28, 1921	Jul 5, 1921
Death:	Sep. 21, 1961	Sep. 3, 1990	Sep. 7, 2002	May 14, 2007
Note:	2D LTINF RES SGT CO B 137 MG BN 38 DIV USA	Wife of 2nd Lt Oscar John Carrico USA	TEC5 US Army Air Forces	(m. 2nd Henry Butterworth)
Burial:	Arlington National Cemetery Arlington, Arlington Co., VA Plot: Sec: 47, Site: 973	Arlington National Cemetery Arlington, Arlington Co., VA Plot: Sec: 47, Site: 979	Arlington National Cemetery Arlington, Arlington Co., VA Plot: Sec 6-HH, Row 22, Site 1	Arlington National Cemetery Arlington, Arlington Co., VA Plot: Sec 6-HH, Row 22, Site 1
Spouse:	Marie Viola Carrico (1899-1990)	Oscar John Carrico (1895-1961)	Arlyne E. Carrico-Butterworth (1921-2007)	John William Carrico (1921-2002
Contributor:	John C. Anderson; 5 Mar 2010	Paul Hays; 19 Dec 2013	Shiver 17 May 2004	Shirley Bybee 16 May 2007
Memorial #:	49164217	121937896	8778464	19395201

10.  C.J. Maxwell.  1949.  Descendants of Gregory Bonnifield (1326-1394). Typescript.  (online at Ancestry.com; comb bound hard copy available from QuintinPublications.com).

Roman numerals refer to the generation; the number is a unique identifier in that generation.  *** means nothing is known.
p. 76	Children of ARTHUR WELLINGTON CARRICO (XXI 50) and Mary Fretwell (1) Jessie E. Carrico (XXII 77) b July 4, 1890; m B. Harry Kelley, Sept. 30, 1913; Masontown, W.Va. (2) *** Walter L. Carrico (XXII 78) b Sept. 4, 1892; m Helen Carroll, .......; 42 James St., Dover, Ohio.  (3) John Oscar Carrico (XXII 79) b March 30, 1895; m Marie Viola Watkins, Oct. 20, 1920; 5535 Fifth St., Washington, D.C.
p. 77	(4) *** Mary Ruth Carrico (XXII 80) b May 8, 1900; m Colie E. Wharton, ......, 1918; Route 5, Morgantown, W.Va.
p. 133	Children of JOHN OSCAR CARRICO (XXII 79) and Mildred Viola Watkins John William Carrico (XXIII 150) b Aug. 28, 1921; m Orlene Etola Stewart, Oct. 22, 1945; 5235 Fifth St., N.W., Washington, D.C.

"Mildred" is an internal error by Maxwell.
Email from John William's daughter says his wife was Arlyne Etola Stowall, not "Orlene Etola Stewart."

11.  Query (posted to the Allegany County MDGenWeb site):

... My father Oscar John CARRICO married mother, Marie Viola WATKINS, Cumberland, Md., Oct 1920. Her father John and I think nm was Patrick WATKINS. Mother was Bridget BURKE. John was a B&O RR Conductor. They lived at 110 Penn Ave., S. Cumberland...

12.  Ken Carrico.  Carrico Genealogy Site:  Descendants of Peter CARRICO (online at www.geocities.com/Heartland/Oaks/15536/peter.html [link died]).

13.  Public Member Trees (online at Ancestry.com):  the six files there give Oscar John's wife as Anne Marie...

14.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com):  the one file there gives Oscar John's wife as Anne Marie...