fewest runs per game allowed in a season by a team 20th century

The Chicago Cubs have the fewest runs allowed per game pitched by a team in a season, with 2.46 in 1906.

	TEAM	R/G	R	G	SEASON	W%	W	L	GS	ERA	SO	CG	SHO	SV	IP	H	ER	HR	BB	HBP	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Cubs	2.46	381	155	1906	.763	116	36	155	1.75	702	125	28	10	1388.1	1,018	270	12	446	53		5,427	20	4.55	2.89	1.57	0.08	12.9	8.2	1.05	.239	2.47	6.60
2	Cubs	2.51	389	155	1909	.680	104	49	155	1.74	680	111	32	11	1409.1	1,094	272	6	364	38		5,494	30	4.34	2.32	1.87	0.04	12.4	6.6	1.03	.247	2.48	6.99
3	Cubs	2.52	390	155	1907	.704	107	45	155	1.73	586	114	31	8	1373.1	1,054	264	11	402	38		5,315	25	3.84	2.63	1.46	0.07	11.0	7.6	1.06	.244	2.56	6.91
4	Athletics	2.72	416	153	1909	.621	95	58	153	1.93	728	110	27	3	1378.0	1,069	296	9	386	65		5,385	31	4.75	2.52	1.89	0.06	13.5	7.2	1.06	.253	2.72	6.98
5	Orioles	2.79	430	154	1972	.519	80	74	154	2.53	788	62	18	21	1371.2	1,116	386	85	395	15	52	5,493	35	5.17	2.59	1.99	0.56	14.3	7.2	1.10	.245	2.82	7.32
6	Brewers	2.83	34	12	1884	.667	8	4	12	2.25	139	12		0	104.0	49	26	1	13			386	7	12.03	1.13	10.69	0.09	36.0	3.4	0.60		2.94	4.24
7	Athletics	2.85	441	155	1910	.680	102	48	155	1.79	789	123	24	5	1421.2	1,103	282	8	450	55		5,503	39	4.99	2.85	1.75	0.05	14.3	8.2	1.09	.261	2.79	6.98
8	White Sox	2.85	450	158	1905	.605	92	60	158	1.99	613	131	15	0	1427.0	1,163	315	11	329	31		5,542	39	3.87	2.07	1.86	0.07	11.1	5.9	1.05	.253	2.84	7.33
9	Cubs	2.85	442	155	1905	.601	92	61	155	2.04	627	133	23	2	1407.1	1,135	319	14	385	51		5,500	21	4.01	2.46	1.63	0.09	11.4	7.0	1.08	.253	2.83	7.26
10	Reds	2.86	401	140	1919	.686	96	44	140	2.23	407	89	23	9	1274.0	1,104	316	21	298	20		5,063	12	2.88	2.11	1.37	0.15	8.0	5.9	1.10	.251	2.83	7.80
11	Braves	2.87	453	158	1916	.586	89	63	158	2.19	644	97	21	11	1415.2	1,206	345	24	325	30		5,612	23	4.09	2.07	1.98	0.15	11.5	5.8	1.08	.258	2.88	7.67
12	Phillies	2.87	445	155	1908	.539	83	71	155	2.10	476	116	22	6	1393.0	1,167	325	8	379	43		5,400	26	3.08	2.45	1.26	0.05	8.8	7.0	1.11	.258	2.88	7.54
13	Giants	2.89	457	158	1917	.636	98	56	158	2.27	551	92	17	14	1426.2	1,221	360	29	327	27		5,721	24	3.48	2.06	1.69	0.18	9.6	5.7	1.09	.249	2.88	7.70
14	Giants	2.9	455	157	1908	.636	98	56	157	2.14	656	95	24	18	1411.0	1,210	336	26	288	35		5,544	18	4.18	1.84	2.28	0.17	11.8	5.2	1.06	.261	2.90	7.72
15	Cubs	2.91	407	140	1919	.536	75	65	140	2.21	495	80	21	5	1265.0	1,127	311	14	294	28		5,109	20	3.52	2.09	1.68	0.10	9.7	5.8	1.12	.260	2.90	8.02
16	Pirates	2.91	448	154	1909	.724	110	42	154	2.07	490	93	21	11	1401.2	1,174	322	12	320	48		5,438	14	3.15	2.05	1.53	0.08	9.0	5.9	1.07	.254	2.88	7.54
17	Red Sox	2.91	457	157	1917	.592	90	62	157	2.20	509	115	14	7	1421.1	1,197	347	12	413	51		5,639	29	3.22	2.62	1.23	0.08	9.0	7.3	1.13	.255	2.89	7.58
18	Cardinals	2.91	472	162	1968	.599	97	65	162	2.49	971	63	27	32	1479.0	1,282	409	82	375	28	62	6,006	30	5.91	2.28	2.59	0.50	16.2	6.2	1.12	.264	2.87	7.80
19	Cubs	2.92	461	158	1908	.643	99	55	158	2.14	668	108	27	12	1433.2	1,137	341	20	437	39		5,611	34	4.19	2.74	1.53	0.13	11.9	7.8	1.10	.251	2.89	7.14
20	White Sox	2.92	464	159	1909	.513	78	74	159	2.05	669	115	26	4	1430.1	1,182	326	8	340	52		5,560	29	4.21	2.14	1.97	0.05	12.0	6.1	1.06	.261	2.92	7.44
21	Naps	2.92	459	157	1908	.584	90	64	157	2.02	548	108	18	5	1424.1	1,172	319	16	328	34		5,488	24	3.46	2.07	1.67	0.10	10.0	6.0	1.05	.253	2.90	7.41
22	Athletics	2.95	457	155	1972	.600	93	62	155	2.58	862	42	15	43	1417.2	1,170	406	96	418	19	41	5,718	29	5.47	2.65	2.06	0.61	15.1	7.3	1.12	.248	2.90	7.43
23	White Sox	2.96	462	156	1917	.649	100	54	156	2.16	517	78	21	21	1424.1	1,236	342	10	413	35		5,645	12	3.27	2.61	1.25	0.06	9.2	7.3	1.16	.263	2.92	7.81
24	Americans	2.97	466	157	1904	.617	95	59	157	2.12	612	148	21	1	1406.0	1,208	331	31	233	29		5,448	22	3.92	1.49	2.63	0.20	11.2	4.3	1.02	.259	2.98	7.73
25	White Sox	2.99	460	154	1906	.616	93	58	154	2.13	543	117	32	4	1375.1	1,212	326	11	255	32		5,345	33	3.55	1.67	2.13	0.07	10.2	4.8	1.07	.267	3.01	7.93