Frio Formation

Operator-reported tops from 19,209 wells across 47 counties, median tops running 900–14,700 ft by county.

Top depth: 400 ft 6,527 ft

3,041 wells shown (sampled from 19,209)

Depth by County

County	Wells	Median Top	Typical Range	CSV
Karnes	1,611	1,500 ft	500–3,200	↓
Refugio	1,484	5,000 ft	4,350–5,897	↓
Wharton	1,302	4,600 ft	3,177–5,983	↓
Jackson	1,205	5,000 ft	3,300–6,214	↓
De Witt	1,152	900 ft	300–2,513	↓
Victoria	935	3,956 ft	2,554–5,785	↓
Fort Bend	832	4,630 ft	2,820–5,318	↓
Goliad	777	2,835 ft	1,940–4,153	↓
Lavaca	723	2,460 ft	450–3,350	↓
Mcmullen	631	1,460 ft	483–1,601	↓
Hidalgo	623	6,700 ft	3,851–8,798	↓
Brazoria	599	7,407 ft	5,121–10,370	↓
Webb	573	3,953 ft	3,071–5,089	↓
Colorado	540	7,980 ft	5,900–9,956	↓
Nueces	501	5,780 ft	3,814–9,349	↓
Matagorda	470	7,737 ft	6,500–9,930	↓
Harris	464	5,682 ft	4,073–6,002	↓
Liberty	424	4,360 ft	2,750–6,705	↓
Colorado	375	3,120 ft	2,460–4,220	↓
Bee	369	2,930 ft	1,550–4,331	↓
San Patricio	351	5,199 ft	3,708–8,988	↓
Jefferson	305	7,636 ft	5,686–9,253	↓
Hardin	287	3,625 ft	1,800–6,182	↓
Duval	248	1,900 ft	738–3,374	↓
Brooks	226	5,665 ft	3,185–8,110	↓
Calhoun	216	7,540 ft	5,358–10,190	↓
Jim Wells	205	3,846 ft	2,573–5,820	↓
Live Oak	205	2,045 ft	141–3,224	↓
Waller	193	3,000 ft	2,450–4,358	↓
Galveston-Sb	161	9,175 ft	7,701–10,875	↓
Orange	150	6,300 ft	5,488–7,785	↓
Kenedy	139	8,010 ft	4,500–12,920	↓
Polk	112	2,846 ft	1,455–3,718	↓
Willacy	101	7,860 ft	5,639–12,333	↓
Newton	99	5,240 ft	3,477–6,152	↓
Aransas	98	8,964 ft	6,950–10,962	↓
Tyler	97	3,138 ft	1,972–4,302	↓
Montgomery	85	2,790 ft	2,540–3,800	↓
Kleberg	84	6,871 ft	4,082–8,617	↓
Jasper	70	4,245 ft	2,422–5,610	↓
Madison	46	2,365 ft	439–5,120	↓
Austin	37	3,200 ft	1,516–3,627	↓
San Jacinto	30	2,840 ft	2,522–3,320	↓
Jim Hogg	29	1,585 ft	1–2,729	↓
Webb	23	1,180 ft	1–5,140	↓
Mustang Is-Sb	13	9,910 ft	8,704–11,951	↓
Nueces	9	14,700 ft	8,663–16,190	↓

Counties with fewer than 5 wells omitted. Depths are measured depth as filed; typical range is the 10th–90th percentile of reported tops — raw filings contain occasional typo depths, so extremes are not shown.