| Item | Obligations |
|---|---|
| Water and Sewer Line and Related Structures Construction | $592M |
| Other Heavy and Civil Engineering Construction | $407M |
| Other Computer Related Services | $355M |
| Computer Systems Design Services | $355M |
| Commercial and Institutional Building Construction | $323M |
| Administrative Management and General Management Consulting Services | $198M |
| Support Activities for Forestry | $166M |
| Custom Computer Programming Services | $140M |
| Engineering Services | $122M |
| Nonscheduled Chartered Passenger Air Transportation | $83.2M |
Water and Sewer Line and Related Structures Construction was Interior's largest contract category, with $592M obligated (13.2% of contract spending).