Sentry started as a one-crane service company in the oilfields of western North Dakota. That’s where the name originated: just one lone Sentry out trying to satisfy the needs of the customer. Sentry grew from there to servicing all the needs of the oilfield including engineering, cranes, trucking, roustabout, welding, workover, and electrical. Today, Sentry operates as a full-service EPC firm (Engineering Procuring, and Constructing).