1.  Marriage Record:

2.  See parents' page for immigration record.

3.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  I found Niels's parents and his brother, Hans, in Carlston Twp., Freeborn Co., MN, but I couldn't find Niels or his sister, Thrine.

4.  1890 Census:  the 1890 Census Population Schedules were destroyed.

5.  1900 Census Every-Name-Index/Images (online at Ancestry.com, Image #3 of 13):  Carlston Twp., Freeborn Co., MN, Roll T623_764, p. 94A, SN 2, SD 1, ED 48, 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	16	17	18	19	20	21	22	23	24	25	26	27	28
31	31	Larsen Niels	Head	W	M	Feb 1858	42	M	10			DK	DK	DK	1880	20	Na	Farmer			Y	Y	Y	O	M	F	29
		______ Regine H	Wife	W	F	Jul 1857	42	M	10	0	0	DK	DK	DK	1889	11					Y	Y	Y
		______ Hans	Bro	W	M	Nov 1864	35	S				DK	DK	DK	1880	29	Na	Farmer	0		Y	Y	Y
		Hansen Emille?	A-Son	W	M	Feb 1889	11	S				MN	DK	NOR				At School		9

Plus four boarders, whom I did not extract.

6.  1910 Census Every-Name-Index/Images (online at Ancestry.com, Image #8 of 14):  Alden Village, Carlston Twp., Freeborn Co., MN, Roll T624_695, p. 244B, SN 4B, SD 1, ED 46, enumerated 29 Apr 1910, official enumeration date 15 Apr 1910 (extracted by Diana Gale Matthiesen):

1910:  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	21	22	23	24	26	27	28	29
77	77	Larsen Nelis	Head	M	W	51	M1	20			Den-Danish	1880	Na	Eng	Farmer	General farm	Emp			Y	Y	O	M	F	76
		______ Geinea	Wife	F	W	52	M1	20	0	0	Den-Danish	1889		Eng	None					Y	Y
		______ Hans	Bro	M	W	45	S				Den-Danish	1880	Na	Eng	Farmer	General farm	Emp			Y	Y
		Jensen Elise	Servant	F	W	21	S				Den-Danish	1908		Eng	Servant	private family	W	N	0	Y	Y
		______ John	Hired Man	M	W	22	S				Den-Danish	1908	al	Eng	Farm laborer	working out	W	N	0	Y	Y

7.  1920 Census Every-Name-Index/Images (online at Ancestry.com, Image #12 of 31):  164 Stevens [St.], St. Paul City (Ward 6), 2nd Precinct, Ramsey Co., MN, Roll T625_853, p. 24B, SN 6B, SD 159, ED 60, enumerated 6 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).
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	17	18	19, 21, 23	20, 22, 24	25	26
*	164	103	132	Larson Nels	Head	O	M	M	W	62	M	1880	Na	1900	Y	Y	Denmark	Danish	Y	None
				______ Regina	Wife			F	W	62	M	1889	Na	1900	Y	Y	Denmark	Danish	Y	None
				______ Hans	Bro			M	W	55	S	1880	Na	1900	Y	Y	Denmark	Danish	Y	None
*Stevens

8.  1930 Census Every-Name-Index/Images (online at Ancestry.com, Image #20 of 79):  164 Stevens St., St. Paul City (Ward 6, Block 337), Ramsey Co., MN, Roll 1117, p. 51A, SN 11A, ED 62-60, SD 8, enumerated 7 Apr 1930with immigrant data, 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	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27
*	164	123	132	Larson Regina	Head	O	5000	R	F	W	73	Wd	32	N	Y	DK	DK	DK	Dainish	1897	Na	Y	None
				______ Hans	Bro in law				M	W	65	S		N	Y	DK	DK	DK	Dainish	1879	Na	Y	None
				Rasmussen Jennie	Lodger				F	W	50	S		N	Y	WI	DK	DK				Y	Seamstress	Dept Store	W
*Stevens St

9.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).