The Seattle Mariners had the most runs by a team in a game in 2012, with 21 runs against the Rangers on May 30, 2012.

Interpreted as:

MLB team most run in a regular-season game 2012

	TEAM	R	DATE	TM		OPP	RESULT	AB	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Mariners	21	5/30/2012	SEA	@	TEX	W 21-8	47	20	7	0	4	20	6	0	8	1	0	54	39	11	0	1	0	0	.426	.481	.830	1.311
2	Athletics	20	8/31/2012	OAK	vs	BOS	W 20-2	44	19	5	0	5	20	2	1	4	0	0	47	39	10	0	0	0	0	.432	.468	.886	1.354
3	Twins	19	7/16/2012	MIN	vs	BAL	W 19-7	41	20	6	0	1	17	5	1	3	1	1	48	29	7	0	1	0	2	.488	.542	.707	1.249
4	White Sox	19	7/3/2012	CWS	vs	TEX	W 19-2	44	21	5	1	4	17	4	0	7	0	0	49	40	10	0	1	1	1	.477	.510	.909	1.419
5	Twins	18	9/4/2012	MIN	@	CWS	W 18-9	41	17	0	1	2	18	8	0	7	0	0	51	25	3	0	2	0	1	.415	.490	.610	1.100
6	Rockies	18	4/27/2012	COL	vs	NYM	W 18-9	43	19	0	2	4	17	4	1	2	1	0	48	35	6	0	0	0	0	.442	.500	.814	1.314
7	Rangers	18	4/17/2012	TEX	@	BOS	W 18-3	46	21	3	0	6	18	8	0	8	0	0	55	42	9	0	1	0	1	.457	.527	.913	1.440
8	Mets	17	6/27/2012	NYM	@	CHC	W 17-1	40	16	6	0	4	17	7	0	4	1	0	48	34	10	0	1	0	2	.400	.479	.850	1.329
9	Rockies	17	4/11/2012	COL	vs	SFG	W 17-8	45	22	8	3	0	15	5	1	5	2	0	52	36	11	1	0	0	1	.489	.549	.800	1.349
10	Phillies	16	9/20/2012	PHI	@	NYM	W 16-1	44	21	1	0	1	16	4	2	2	0	0	50	25	2	0	0	0	2	.477	.540	.568	1.108
11	Giants	16	8/3/2012	SFG	@	COL	W 16-4	44	16	4	1	2	14	7	0	5	1	1	52	28	7	1	0	0	0	.364	.451	.636	1.087
12	Athletics	16	7/25/2012	OAK	@	TOR	W 16-0	41	14	6	0	3	15	7	0	7	1	0	48	29	9	0	0	1	0	.341	.438	.707	1.145
13	Brewers	16	5/20/2012	MIL	vs	MIN	W 16-4	39	17	2	0	3	16	4	3	5	0	0	47	28	5	0	1	0	1	.436	.511	.718	1.229
14	Indians	15	9/30/2012	CLE	vs	KCR	W 15-3	42	19	4	0	1	14	5	2	11	1	0	49	26	5	0	0	0	1	.452	.531	.619	1.150
15	Indians	15	9/23/2012	CLE	@	KCR	W 15-4	43	16	1	1	2	13	8	0	3	2	0	51	25	4	0	0	1	0	.372	.471	.581	1.052
16	Diamondbacks	15	9/21/2012	ARI	@	COL	W 15-5	45	19	5	0	2	15	8	0	9	3	0	54	30	7	0	1	1	0	.422	.500	.667	1.167
17	Brewers	15	8/27/2012	MIL	@	CHC	W 15-4	47	21	3	0	5	14	3	0	7	2	0	50	39	8	0	0	0	2	.447	.480	.830	1.310
18	Giants	15	8/8/2012	SFG	@	STL	W 15-0	39	15	3	0	1	14	7	0	4	0	0	49	21	4	1	2	0	1	.385	.458	.538	.997
19	Rangers	15	8/2/2012	TEX	vs	LAA	W 15-9	42	18	6	0	2	15	5	1	9	1	0	48	30	8	0	0	0	0	.429	.500	.714	1.214
20	Angels	15	7/30/2012	LAA	@	TEX	W 15-8	42	16	2	0	4	15	4	0	9	1	1	46	30	6	0	0	2	0	.381	.435	.714	1.149
21	Blue Jays	15	7/22/2012	TOR	@	BOS	W 15-7	39	18	2	0	4	15	5	0	8	0	0	48	32	6	2	2	0	3	.462	.500	.821	1.321
22	Red Sox	15	6/20/2012	BOS	vs	MIA	W 15-5	39	16	2	0	4	14	5	0	6	0	0	44	30	6	0	0	1	1	.410	.477	.769	1.247
23	Braves	15	5/2/2012	ATL	vs	PHI	W 15-13	47	19	1	0	2	15	3	0	9	0	1	51	26	3	0	1	0	1	.404	.431	.553	.985
24	Yankees	15	4/21/2012	NYY	@	BOS	W 15-9	42	16	4	0	3	15	8	0	9	1	0	50	29	7	0	0	2	1	.381	.480	.690	1.170
25	Yankees	14	10/3/2012	NYY	vs	BOS	W 14-2	37	15	3	0	4	14	7	1	5	1	0	46	30	7	0	1	0	1	.405	.500	.811	1.311