Sorin Cosoveanu brought the Cameroon Statistical Yearbook (source [1]) to my attention. That's where I got the population and area data in the first (yellow) table, below.

Cameroon is divided into ten regions, which are subdivided into 58 départements (departments). (The departments in Nord-Ouest and Sud-Ouest regions, which used to be part of the British mandate, are sometimes called "divisions".) The departments are further subdivided into 315 arrondissements (as of 1999), and then into districts. The table below shows all of the departments of Cameroon. Some of the department names have been changed to their French forms.

Department	HASC	Population	Area(km.²)	Capital
Bamboutos	CM.OU.BA	318,848	1,173	Mbouda
Bénoué	CM.NO.BE	568,793	13,614	Garoua
Boumba-et-Ngoko	CM.ES.BN	116,702	30,389	Yokadouma
Boyo	CM.NW.BO	169,725	1,592	Fundong
Bui	CM.NW.BU	322,877	2,297	Kumbo
Diamaré	CM.EN.DI	566,921	4,665	Maroua
Dja-et-Lobo	CM.SU.DL	173,219	19,911	Sangmelima
Djerem	CM.AD.DJ	89,382	13,283	Tibati
Donga-Mantung	CM.NW.DM	337,533	4,279	Nkambé
Fako	CM.SW.FA	534,854	2,093	Limbe
Faro	CM.NO.FA	81,472	11,785	Poli
Faro-et-Déo	CM.AD.FD	66,442	10,435	Tignere
Haute-Sanaga	CM.CE.HS	115,305	11,854	Nanga-Eboko
Haut-Nkam	CM.OU.HN	203,251	958	Bafang
Haut-Nyong	CM.ES.HN	216,768	36,384	Abong-Mbang
Hauts-Plateaux	CM.OU.HP	117,008	415	Baham
Kadey	CM.ES.KA	192,927	15,884	Batouri
Koung-Khi	CM.OU.KK	121,794	353	Badjoun
Koupé-Manengouba	CM.SW.KM	123,011	3,404	Bangem
Lebialem	CM.SW.LE	144,560	617	Menji
Lekié	CM.CE.LE	354,864	2,989	Monatele
Logone-et-Chari	CM.EN.LC	405,035	12,133	Kousseri
Lom-et-Djerem	CM.ES.LD	228,691	26,345	Bertoua
Manyu	CM.SW.MN	177,389	9,565	Mamfe
Mayo-Banyo	CM.AD.MB	134,902	8,520	Banyo
Mayo-Danay	CM.EN.MD	522,782	5,303	Yagoua
Mayo-Kani	CM.EN.KA	338,448	5,033	Kaele
Mayo-Louti	CM.NO.ML	334,312	4,162	Guider
Mayo-Rey	CM.NO.MA	242,441	36,529	Tcholliré
Mayo-Sava	CM.EN.MS	313,413	2,736	Mora
Mayo-Tsanaga	CM.EN.MT	574,864	4,393	Mokolo
Mbam-et-Inoubou	CM.CE.MI	153,020	7,125	Bafia
Mbam-et-Kim	CM.CE.MK	64,540	25,906	Ntui
Mbéré	CM.AD.MR	185,473	14,267	Meinganga
Mefou-et-Afamba	CM.CE.MM	89,805	3,358	Mfou
Mefou-et-Akono	CM.CE.MN	57,051	1,329	Ngoumou
Meme	CM.SW.MM	300,318	3,105	Kumba
Menchum	CM.NW.MC	157,173	4,469	Wum
Menoua	CM.OU.ME	372,244	1,380	Dschang
Mezam	CM.NW.ME	465,644	1,745	Bamenda
Mfoundi	CM.CE.MF	1,248,236	297	Yaoundé
Mifi	CM.OU.MF	290,758	402	Bafoussam
Momo	CM.NW.MO	213,402	1,792	Mbengwi
Moungo	CM.LT.MU	452,722	3,723	Nkongsamba
Mvila	CM.SU.MV	163,826	8,697	Ebolowa
Ndian	CM.SW.ND	129,659	6,626	Mundemba
Ndé	CM.OU.ND	123,661	1,524	Bangangte
Ngo-Ketunjia	CM.NW.NK	174,173	1,126	Ndop
Nkam	CM.LT.NK	66,979	6,291	Yabassi
Noun	CM.OU.NO	434,542	7,687	Foumban
Nyong-et-Kéllé	CM.CE.NK	145,181	6,362	Eseka
Nyong-et-Mfoumou	CM.CE.NM	130,321	6,172	Akonolinga
Nyong-et-So'o	CM.CE.NS	142,907	3,581	Mbalmayo
Océan	CM.SU.OC	133,062	11,280	Kribi
Sanaga-Maritime	CM.LT.SM	167,661	9,311	Edéa
Vallée-du-Ntem	CM.SU.VN	64,747	7,303	Ambam
Vina	CM.AD.VI	247,427	17,196	Ngaoundéré
Wouri	CM.LT.WO	1,514,978	923	Douala
58 departments		15,731,000	446,050
HASC: Hierarchical administrative subdivision codes. The middle two letters identify the region. For key, see "Administrative Subdivisions of Countries". Population: 2001, projected (source [1]). Area: (source [1]).

Change history:

1. Before ~1972, the departments and divisions were the primary subdivisions of Cameroon. They are described on the Regions of Cameroon page.
2. ~1975: Bamenda division (capital Bamenda) split into Bui, Mezam, and Momo divisions. Ndian division formed from parts of Kumba and Victoria. The name of the remaining part of Kumba changed to Meme; the name of the remaining part of Victoria changed to Fako, and the name of its capital, Victoria, changed to Limbe. The name of Mamfe division changed to Manyu; the name of Nkambe division changed to Donga-Mantung; the name of Wum division changed to Menchum. The table below shows the resulting situation.

Department	Prov	Population	Area(km.²)	Capital
Adamaoua	ND	238,000	63,691	Ngaoundéré
Bamboutos	OT	139,000	1,157	Mbouda
Bamoun	OT	184,000	7,700	Foumban
Bénoué	ND	339,000	65,576	Garoua
Boumba-Nkogo	ET	38,000	30,394	Yokadouma
Bui	NT	118,000	2,104	Kumbo
Diamaré	ND	381,000	9,701	Maroua
Dja-et-Lobo	CS	108,000	19,862	Sangmélima
Donga-Mantung	NT	139,000	4,368	Nkambe
Fako	SO	104,000	2,086	Limbe
Haute-Sanaga	CS	54,000	11,878	Nanga-Eboko
Haut-Nkam	OT	113,000	1,053	Bafang
Haut-Nyong	ET	105,000	36,378	Abong Mbang
Kadeï	ET	63,000	15,886	Batouri
Kribi	CS	60,000	11,244	Kribi
Lékié	CS	176,000	2,987	Obala
Logone-et-Chari	ND	94,000	12,115	Fort Foureau
Lom-et-Djerem	ET	63,000	26,353	Bertoua
Manyu	SO	127,000	9,343	Mamfe
Margui-Wandala	ND	337,000	7,125	Mokolo
Mayo-Danaï	ND	193,000	5,305	Yagoua
Mbam	CS	150,000	32,936	Bafia
Méfou	CS	301,000	4,951	Yaoundé
Meme	SO	143,000	8,018	Kumba
Menchum	NT	147,000	6,218	Wum
Ménoua	OT	197,000	1,339	Dschang
Mezam	NT	242,000	3,210	Bamenda
Mifi	OT	251,000	1,183	Bafoussam
Momo	NT	91,000	1,912	Mbengüi
Moungo	LI	206,000	3,595	Nkongsamba
Ndé	OT	101,000	1,440	Bangangté
Ndian	SO	85,000	5,124	Mundemba
Nkam	LI	33,000	6,445	Yabassi
Ntem	CS	119,000	16,004	Ebolowa
Nyong-et-Kéllé	CS	75,000	6,382	Eséko
Nyong-et-Mfoumou	CS	73,000	6,178	Akonolinga
Nyong-et-Soo	CS	77,000	3,614	Mbalmayo
Sanaga-Maritime	LI	121,000	9,070	Edéa
Wouri	LI	251,000	1,129	Douala
39 departments		5,836,000	465,054
Prov: CS = Centre-Sud; ES = Est; LT = Littoral; ND = Nord; NW = Nord-Ouest; OU = Ouest; SW = Sud-Ouest Population: 1970 estimate

1. 1983-08-22: Centre-Sud province split into two provinces: Centre and Sud, where Sud province consisted of Dja-et-Lobo, Kribi, and Ntem departments. Nord province split into three provinces: Adamaoua, Nord, and Extrême-Nord, where Adamaoua consisted of Adamaoua department only, and Nord consisted of Bénoué department only.
2. ~1984: Adamaoua department split into Djerem, Faro-Deo, Mayo-Banyo, Mbere, and Vina; name of Bamoun department changed to Noun; Faro, Mayorey, and Mayo-Louti departments split from Bénoué; Kaele department split from Diamaré; Margui-Wandala department split into Mayo-Sava and Mayo-Tsanaga; Mfoundi department split from Méfou.
3. ~1986: Capital of Lékié department moved from Obala to Monatele; name of Kribi department changed to Océan.

Department	HASC	Code	Pop-1987	Pop-1976	Area(km²)	Capital
Bamboutos	CM.OU.BA	H1	213,488	155,193	1,170	Mbouda
Bénoué	CM.NO.BE	F1	385,381	172,001	13,614	Garoua
Boumba-Nkogo	CM.ES.BN	C1	82,102	53,323	30,630	Yokadouma
Bui	CM.NW.BU	G1	219,695	142,015	2,300	Kumbo
Diamaré	CM.EN.DI	D1	383,949	281,881	4,665	Maroua
Dja-et-Lobo	CM.SU.DL	I1	125,869	99,638	19,910	Sangmelima
Djerem	CM.AD.DJ	A1	59,369	32,830	13,283	Tibati
Donga-Mantung	CM.NW.DM	G2	228,251	172,712	4,280	Nkambe
Fako	CM.SW.FA	J1	251,129	157,032	2,060	Limbe
Faro	CM.NO.FA	F2	57,671	52,277	13,624	Poli
Faro-Deo	CM.AD.FD	A2	43,904	29,844	10,435	Tignere
Haute-Sanaga	CM.CE.HS	B1	79,938	56,189	11,850	Nanga Eboko
Haut-Nkam	CM.OU.HN	H2	140,941	104,467	960	Bafang
Haut-Nyong	CM.ES.HN	C2	150,220	115,848	36,040	Abong-Mbang
Kadeï	CM.ES.KA	C3	130,715	88,197	15,910	Batouri
Kaele	CM.EN.KA	D2	228,737	186,434	5,033	Kaele
Lékié	CM.CE.LE	B2	239,500	203,159	2,990	Monatele
Logone-et-Chari	CM.EN.LC	D3	278,854	147,321	10,183	Kousseri
Lom-et-Djerem	CM.ES.LD	C4	153,696	85,482	26,320	Bertoua
Manyu	CM.SW.MA	J2	217,568	152,678	10,180	Mamfe
Mayo-Banyo	CM.AD.MB	A3	92,668	68,252	8,520	Banyo
Mayo-Danaï	CM.EN.MD	D4	354,181	225,114	5,300	Yagoua
Mayo-Louti	CM.NO.ML	F3	255,735	169,738	4,162	Guider
Mayorey	CM.NO.MA	F4	164,316	67,264	36,529	Tchollire
Mayo-Sava	CM.EN.MS	D5	209,718	160,432	2,736	Mora
Mayo-Tsanaga	CM.EN.MT	D6	425,427	304,163	4,393	Mokolo
Mbam	CM.CE.MB	B3	206,799	164,421	33,030	Bafia
Mbere	CM.AD.MR	A4	126,859	89,912	14,267	Meinganga
Méfou	CM.CE.ME	B4	141,166	124,367	4,155	Mfou
Meme	CM.SW.ME	J3	281,615	196,470	6,510	Kumba
Menchum	CM.NW.MN	G3	218,802	183,055	6,060	Wum
Ménoua	CM.OU.ME	H3	250,009	201,409	1,380	Dschang
Mezam	CM.NW.MZ	G4	429,285	298,911	2,870	Bamenda
Mfoundi	CM.CE.MF	B5	704,368	313,206	615	Yaoundé
Mifi	CM.OU.MI	H4	356,979	242,316	1,170	Bafoussam
Momo	CM.NW.MO	G5	141,771	118,219	1,790	Mbengwi
Moungo	CM.LT.MU	E1	338,459	275,456	3,720	Nkongsamba
Ndé	CM.OU.ND	H5	82,409	67,942	1,520	Bangangte
Ndian	CM.SW.ND	J4	90,571	74,180	6,160	Mundemba
Nkam	CM.LT.NK	E2	41,170	34,373	6,300	Yabassi
Noun	CM.OU.NO	H6	287,375	197,529	7,690	Foumban
Ntem	CM.SU.NT	I2	158,840	128,514	16,000	Ebolowa
Nyong-et-Kéllé	CM.CE.NK	B6	99,535	86,668	6,360	Eseka
Nyong-et-Mfoumou	CM.CE.NM	B7	86,838	72,865	6,170	Akonolinga
Nyong-et-Soo	CM.CE.NS	B8	97,396	77,805	3,580	Mbalmayo
Océan	CM.SU.OC	I3	92,528	66,776	11,280	Kribi
Sanaga-Maritime	CM.LT.SM	E3	135,818	112,550	9,310	Edea
Vina	CM.AD.VI	A5	168,242	102,328	15,600	Ngaoundéré
Wouri	CM.LT.WO	E4	836,380	419,077	890	Douala
49 departments			10,546,236	7,131,833	463,504
HASC: Hierarchical administrative subdivision codes. The middle two letters identify the province. For key, see "Administrative Subdivisions of Countries". Code: Keyed to the departments on this map . Pop-1987: 1987-04-10 census Pop-1976: 1976-04-09 census Source for populations and area: Saint-Julien T., Grasland C. et al.: "Itineraires géographiques en Pays Statistique", Feuilles de Géographie, Hors-Série nº 1. Université de Paris, Paris. 1998. Capital: The capital of a department is called a préfecture.

1. ~1995: Mbam department split into Mbam-et-Inoubou and Mbam-et-Kim; Méfou split into Mefou-et-Afamba and Mefou-et-Akono; Ngo-Ketunjia department split from Mezam; Hauts-Plateaux and Koung-Khi departments split from Mifi; Ntem department split into Mvila and Vallée du Ntem. Name of Kaele department changed to Mayo-Kani.
2. ~1998: Lebialem department split from Manyu; Kupe-Manenguba department split from Meme; Boyo department split from Menchum.

Other names of subdivisions:

Except where otherwise labeled, these are variant spellings that I've found. The word "et" can be replaced by "and" to create an English form.

1. Bénoué: Benue
2. Boumba-et-Ngoko: Boumba-Nkogo, Bumba-Nkogo
3. Bui: Mbui
4. Dja-et-Lobo: Ja-et-Lobo
5. Djerem: Jerem
6. Donga-Mantung: Ndonga Mantung, Ndonga Mentum; Nkambe (obsolete)
7. Faro-et-Deo: Faro-Déo
8. Haute-Sanaga: Upper Sanaga
9. Haut-Nkam: Upper Nkam
10. Haut-Nyong: Upper Nyong
11. Hauts-Plateaux: Upper Plateaux
12. Kadey: Kadeï
13. Koung-Khi: Koung-Ki
14. Koupé-Manengouba: Koupé et Manengouba, Kupe-Manenguba
15. Lom-et-Djerem: Lom-et-Jerem
16. Mayo-Banyo: Maya Banyo
17. Mayo-Danay: Mayo-Danai
18. Mayo-Kani: Kaele (obsolete)
19. Mayo-Louti: Mayo-Luti
20. Mayo-Tsanaga: Maya Tsanaga, Mayo Sanaga, Mayo-Tsanga
21. Mbam-et-Inoubou: Mbam et Inougou
22. Mefou-et-Afamba: Mefou Afamba
23. Menchum: Mentchum, Mentum
24. Menoua: Menua
25. Mfoundi: Mfundi
26. Moungo: Mungo
27. Mvila: Ntem
28. Ndian: Ndan, Ndiang
29. Ngo-Ketunjia: Ngocketunja, Ngogetunjia, Ngok Etunjia
30. Noun: Bamoun (obsolete); Nun
31. Nyong-et-Kéllé: Nyong-et-Kele
32. Nyong-et-Mfoumou: Myong and Mfoumou, Nyong et Mfoumo, Nyong-et-Mfumu
33. Nyong-et-So'o: Myong and So'o, Nyong-et-So, Nyong et Soo
34. Océan: Kribi (obsolete)
35. Wouri: Wuri

Sources:

1. [1] "Annuaire Statistique du Cameroun 2006", Institut National de la Statistique du Cameroun.