COS LLC
dba CASTLE OILFIELD SERVICES
WILLISTON, ND
04/16/2014
20
Power Units
19
Drivers
Current
as of today
Active · 20 power units · 19 drivers · Williston, ND
2026
Apr 3, 2026
Safety rating: Satisfactory
~Feb 2026
Fleet grew 14 → 20 power units
~Feb 2026
Driver count changed 14 → 19
~Feb 2026
Officer change
JASON PAHL → PENNY BROWN
Jan 29, 2026
MCS-150 biennial update filed
Reported mileage: 251,164 (2025)
Reported power units: 12 → 20
Reported drivers: 12 → 19
Reported trailers: 2
2023
Mar 8, 2023
MCS-150 biennial update filed
Reported mileage: 201,996 (2022)
Reported power units: 10 → 12
Reported drivers: 12
Reported trailers: 2
2022
Apr 28, 2022
MCS-150 biennial update filed
Reported mileage: 257,199 (2021)
Reported power units: 17 → 10
Reported drivers: 15 → 12
Feb 2, 2022
MCS-150 biennial update filed
Reported mileage: 257,199 (2021)
Reported power units: 12 → 17
Reported drivers: 15
2021
Apr 30, 2021
MCS-150 biennial update filed
Reported mileage: 197,330 (2020)
Reported power units: 19 → 12
Reported drivers: 19 → 15
2020
Feb 6, 2020
MCS-150 biennial update filed
Reported mileage: 513,381 (2018)
Reported power units: 19
Reported drivers: 19
2014
Apr 16, 2014
DOT registered
Company registered with the FMCSA.