| Item | Obligations |
|---|---|
| Water and Sewer Line and Related Structures Construction | $752M |
| Commercial and Institutional Building Construction | $542M |
| Other Computer Related Services | $520M |
| Computer Systems Design Services | $516M |
| Other Heavy and Civil Engineering Construction | $494M |
| Administrative Management and General Management Consulting Services | $312M |
| Custom Computer Programming Services | $294M |
| Support Activities for Forestry | $288M |
| Engineering Services | $193M |
| Highway, Street, and Bridge Construction | $192M |
Water and Sewer Line and Related Structures Construction was Interior's largest contract category, with $752M obligated (11.1% of contract spending).