Sorin Cosoveanu sent me a copy of the local government constitution for Kili/Bikini/Ejit, which defines its name to be that.

Note: the Republic of the Marshall Islands is so small that I have listed it as having only one primary division, consisting of the entire country. The table on this page shows municipalities, which I classify as secondary divisions.

There are various official sources that show the Marshall Islands divided into 24 municipalities, and others show them as 33 municipalities. My editorial decision is that something must have happened around 2000 that effectively merged some of the uninhabited atolls with other municipalities. Nuclear testing conducted by the U.S. in 1946-1958 forced the relocation of many Marshallese, who tend to identify with their ancestral homes. That would provide a rationale for merging the abandoned atoll with the municipality of relocation. This is only a hypothesis. In any case, there seem to have been name changes that imply two such mergers: Enewetak with Ujelang and Bikini with Kili.

For as long as I've been tracking them, there have been distinct FIPS 6-4 codes for 33 municipalities. When GEC first issued codes for the divisions of the Marshall Islands, in its Update 12, dated 2013-06-30, it had distinct codes for 24 municipalities, as shown here.

An update to ISO 3166-2, issued on 2014-11-03, changes the names of two municipalities from Enewetak to Enewetak and Ujelang and from Kili to Bikini and Kili.

ISO 3166-2 Newsletter number II-1, dated 2010-02-03, has changes to the listing for the Marshall Islands. Some of the island names have been changed to variants. Ujelang (uninhabited) has been dropped from the listing, and Jabat (inhabited) has been added.

International standard ISO 3166-2 was published on 1998-12-15. It superseded ISO/DIS 3166-2 (draft international standard), which came out in fall 1996. The draft standard shows no administrative subdivisions of the Marshall Islands. The final standard shows 24 municipalities. They appear to be a subset of the 33 municipalities recognized by FIPS PUB 6-4. It also shows two chains of islands, which are a higher level of subdivision than the municipalities (i.e., each chain includes numerous municipalities).

The change is inconsistent with ISO's usual practice. About twenty small island nations had subdivisions that were listed in the draft standard, but were dropped from the final standard as being "not relevant". The Marshall Islands is even smaller than many of those twenty.

Municipalities	HASC	GEC	ISO	Chain	Population	Area(km.²)	Area(mi.²)
Ailinglaplap	MH.MH.AP	RM01	ALL	Ralik	1,729	15	6
Ailuk	MH.MH.AK	RM02	ALK	Ratak	339	5	2
Arno	MH.MH.AR	RM03	ARN	Ratak	1,794	13	5
Aur	MH.MH.AU	RM04	AUR	Ratak	499	6	2
Ebon	MH.MH.EB	RM06	EBO	Ralik	706	6	2
Enewetak and Ujelang	MH.MH.EU	RM07	ENI	Ralik	664	8	3
Jabat	MH.MH.JB	RM08	JAB	Ralik	84	1	0
Jaluit	MH.MH.JL	RM09	JAL	Ralik	1,788	11	4
Kili/Bikini/Ejit	MH.MH.BK	RM05	KIL	Ralik	557	7	3
Kwajalein	MH.MH.KW	RM10	KWA	Ralik	11,408	16	6
Lae	MH.MH.LA	RM11	LAE	Ralik	347	1	0
Lib	MH.MH.LB	RM12	LIB	Ralik	155	1	0
Likiep	MH.MH.LP	RM13	LIK	Ratak	401	10	4
Majuro	MH.MH.MJ	RM14	MAJ	Ratak	27,797	10	4
Maloelap	MH.MH.ML	RM15	MAL	Ratak	682	10	4
Mejit	MH.MH.ME	RM16	MEJ	Ratak	348	2	1
Mili	MH.MH.MI	RM17	MIL	Ratak	738	16	6
Namorik	MH.MH.NK	RM18	NMK	Ralik	508	3	1
Namu	MH.MH.NU	RM19	NMU	Ralik	780	6	2
Rongelap	MH.MH.RO	RM20	RON	Ralik	79	13	5
Ujae	MH.MH.UJ	RM21	UJA	Ralik	364	2	1
Utirik	MH.MH.UB	RM22	UTI	Ratak	435	6	2
Wotho	MH.MH.WH	RM23	WTH	Ralik	97	4	2
Wotje	MH.MH.WE	RM24	WTJ	Ratak	859	10	4
24 municipalities					53,158	182	70
HASC: Hierarchical administrative subdivision codes. GEC: Code from Geopolitical Entities and Codes. ISO: Municipality codes from ISO 3166-2. For full identification in a global context, prefix "MH-" to the code (ex: MH-KWA represents Kwajalein). Chain: The atolls of the Marshall Islands lie in two rows, the Ralik chain (ISO code: L) to the west and the Ratak chain (T) to the east. Population: 2011-04-05 census.

Other names of subdivisions:

Source [4] has an unusually thorough list of alternate names for the atolls. In a few cases, the names in the table above are missing, but the identification should be straightforward. It also gives the latitudes and longitudes of the islands. (List of sources is on the Marshall Islands page.)

1. Ailinglaplap: Ailinglapalap (variant)
2. Bokak: Taongi (variant)
3. Enewetak: Eniwetok (variant)
4. Jabat: Jabwot (variant)
5. Namorik: Namdrik (variant)
6. Taka: Toke (variant)
7. Ujelang: Agelong (variant)
8. Utirik: Utrik (variant)

Change history: 

1. 1947-04-02: Following the defeat of Japan in World War II, the Trust Territory of the Pacific Islands was created and granted in trust to the United States. It was divided into districts (Kosrae, Marshall Islands, Northern Mariana Islands, Palau, Ponape, Truk, and Yap). Marshall Islands had had two subdistricts since 1946-12: Kwajalein and Majuro, with capitals at Kwajalein and Uliga, respectively.
2. 1986-10-21: The Marshall Islands became a freely associated state of the United States.
3. 1991-09-17: Marshall Islands became fully independent as the Republic of the Marshall Islands.
4. 1999: According to FIPS PUB 6-4, the Marshall Islands contained the 33 municipalities shown in the table below.
5. ~2000: Nominally, Kili merged with Bikini to form Kili/Bikini/Ejit; Ujelang merged with Enewetak to form Enewetak and Ujelang; Jemo merged with Likiep; Ailinginae and Rongrik merged with Rongelap; Bikar, Toke, and Bokak merged with Utirik; Erikub merged with Wotje. Some of the merged municipalities have incompatible FIPS 6-4 codes. None of them had incompatible FIPS 10-4 codes. Either the merged entities had the same 10-4 codes (duplicates), or all but one of them had no 10-4 codes at all. As for ISO 3166-2 codes, all but one of the merged entities had no ISO code in each case.
6. There seems to be no clear indication of which uninhabited municipalities merged with which others. To specify that, I relied on whatever clues I could find: the renaming of two municipalities, geographic proximity, and statements in Wikipedia . That's why I said "Nominally."

Municipalities	HASC	F-10	F-6	ISO	Chain	Population	Area(km.²)	Area(mi.²)
Ailinginae	MH.MH.AI		007		Ralik	0	3	1
Ailinglaplap	MH.MH.AP	RM01	010	ALL	Ralik	1,729	15	6
Ailuk	MH.MH.AK	RM02	030	ALK	Ratak	339	5	2
Arno	MH.MH.AR	RM03	040	ARN	Ratak	1,794	13	5
Aur	MH.MH.AU	RM04	050	AUR	Ratak	499	6	2
Bikar	MH.MH.BR		060		Ratak	0	0	0
Bikini	MH.MH.BN	RM05	070		Ralik	9	6	2
Bokak	MH.MH.BO		073		Ratak	0	3	1
Ebon	MH.MH.EB	RM06	080	EBO	Ralik	706	6	2
Enewetak	MH.MH.EN	RM07	090	ENI	Ralik	664	6	2
Erikub	MH.MH.ER		100		Ratak	0	2	1
Jabat	MH.MH.JB	RM08	110	JAB	Ralik	84	1	0
Jaluit	MH.MH.JL	RM09	120	JAL	Ralik	1,788	11	4
Jemo	MH.MH.JE		130		Ratak	0	0	0
Kili	MH.MH.KI	RM05	140	KIL	Ralik	548	1	0
Kwajalein	MH.MH.KW	RM10	150	KWA	Ralik	11,408	16	6
Lae	MH.MH.LA	RM11	160	LAE	Ralik	347	1	1
Lib	MH.MH.LB	RM12	170	LIB	Ralik	155	1	0
Likiep	MH.MH.LK	RM13	180	LIK	Ratak	401	10	4
Majuro	MH.MH.MJ	RM14	190	MAJ	Ratak	27,797	10	4
Maloelap	MH.MH.ML	RM15	300	MAL	Ratak	682	10	4
Mejit	MH.MH.ME	RM16	310	MEJ	Ratak	348	2	1
Mili	MH.MH.MI	RM17	320	MIL	Ratak	738	16	6
Namorik	MH.MH.NK	RM18	330	NMK	Ralik	508	3	1
Namu	MH.MH.NU	RM19	340	NMU	Ralik	780	6	2
Rongelap	MH.MH.RL	RM20	350	RON	Ralik	79	8	3
Rongrik	MH.MH.RR		360		Ralik	0	2	1
Toke	MH.MH.TO		385		Ratak	0	1	0
Ujae	MH.MH.UJ	RM21	390	UJA	Ralik	364	2	1
Ujelang	MH.MH.UL	RM07	400	UJL	Ralik	0	2	1
Utirik	MH.MH.UT	RM22	410	UTI	Ratak	435	2	1
Wotho	MH.MH.WH	RM23	420	WTH	Ralik	97	4	2
Wotje	MH.MH.WJ	RM24	430	WTJ	Ratak	859	8	3
33 municipalities						53,158	181	70
HASC: Hierarchical administrative subdivision codes. F-10: Code from Geopolitical Entities and Codes (see note). F-6: Code from FIPS PUB 6-4. ISO: Municipality codes from ISO 3166-2. For full identification in a global context, prefix "MH-" to the code (ex: MH-KWA represents Kwajalein). Chain: The atolls of the Marshall Islands lie in two rows, the Ralik chain (ISO code: L) to the west and the Ratak chain (T) to the east. Population: 2011-04-05 census.

 

U.S. government standards FIPS 6-4 and FIPS 10-4 were withdrawn on 2008-09-02. I have preserved those codes in the table above as a historical record.

FIPS PUB 6-4 divides the Marshall Islands into municipalities. It assigns a three-digit code to each of them. FIPS 5-2 provides a code for each state, territory, or freely associated state of the U.S. For the Marshall Islands, it specifies 68. When the FIPS 5-2 and 6-4 codes are concatenated, as in 68430 for Wotje, the result is a code that uniquely identifies a county-equivalent unit in the United States.

Population history:

Municipality	1958	1967	1973	1980	1988	1999	2011
Ailinglaplap	1,288	1,195	1,100	1,385	1,715	1,959	1,729
Ailuk	419	384	335	413	488	513	339
Arno	1,037	1,273	1,120	1,487	1,656	2,069	1,794
Aur	241	361	300	444	438	537	499
Bikini	0	0	75	0	10	13	9
Ebon	819	836	740	887	741	902	706
Enewetak	0	0	0	542	715	853	664
Jabat	0	0	70	72	112	95	84
Jaluit	1,098	1,113	925	1,450	1,709	1,669	1,788
Kili	267	309	360	489	602	774	548
Kwajalein	1,284	3,540	5,469	6,624	9,311	10,902	11,408
Lae	165	131	154	237	319	322	347
Lib	44	142	98	98	115	147	155
Likiep	636	430	406	481	482	527	401
Majuro	3,415	5,249	10,290	11,791	19,664	23,676	27,797
Maloelap	454	494	432	614	796	856	682
Mejit	346	320	271	325	445	416	348
Mili	412	582	538	763	854	1,032	738
Namorik	523	547	431	617	814	772	508
Namu	482	597	493	654	801	903	780
Rongelap	264	189	165	235	0	19	79
Ujae	167	191	209	309	448	440	364
Ujelang	172	251	342	0	0	0	0
Utirik	198	269	217	336	409	433	435
Wotho	71	0	61	85	90	145	97
Wotje	361	396	425	535	646	866	859
Total	14,163	18,799	25,045	30,873	43,380	50,840	53,158

 

From 1946 to 1980, the population of Enewetak was evacuated to Ujelang because of nuclear testing. A similar, but more complex, evacuation removed the people of Bikini to Kili. In the 1973 census, 19 people were included in the total but did not state their municipality. Municipalities are not listed here if they had zero population during the entire period (source [3]).