1.  Marriage Record:

2.  Family Quest Archives:  Missouri 1870 Census Index.  Heritage Quest ACD-0019:  unmarried, still living with his parents.

3.  LDS.  Family Search: Census Records: 1880 United States (online at FamilySearch.org):

Census Place: Kansas City, Jackson, Missouri
Source: FHL Film #1254693; NARA Film #T9-0693; Pg 384C
	Relation	Sex	Marr	Race	Age	Birthplace	Occupation	Fa	Mo
Joseph C. DAVIS	Self	M	M	W	42	MO	School Teacher	VA	KY
Sallie M. DAVIS	Wife	F	M	W	33	MO	School Teacher	KY	MO
Paul R. DAVIS	Son	M	S	W	8	MO	At School	MO	MO
Eliza DAVIS	Sister	F	S	W	35	MO	Housekeeper	KY	KY
Thomas HANEY	Other	M	S	W	30	IRE	Laborer	IRE	IRE
James RAFTER	Other	M	S	W	23	ENG	Coal Miner	IRE	IRE
James PHILLIPS	Other	M	S	W	28	IRE	Coal Miner	IRE	IRE

Joseph's grandfather was born in VA, but his father was born in KY.

4.  1890 Census:  the 1890 census population schedules were destroyed.

5.  1900 Census Index/Microfilm (online at Genealogy.com):  2612 East Eleventh, Kansas City, Ward 8, Jackson Co., MO, p. 67A, SN 8, SD 5, ED 70, enumerated 6 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):

1900:  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	19	20	22	23	24	25	27
147	159	Estill, Robt G	Head	W	M	Oct 1835	64	M	25			MO	KY	MO	Real Estate Agt.	0	Y	Y	Y	R	H
		______, Mary A	Wife	W	F	Oct 1848	51	M	25	4	4	MO	VA	MO			Y	Y	Y
		[Robert & Mary's four children]
		Davis, Sarah M	Sister	W	F	May 1848	52	Wd		1	1	MO	KY	MO	Teacher	3	Y	Y	Y