1. In/at a location where something important is happening
have people on the ground to observe something first-hand
'On the ground' means 'the thing of concern'. This could be a building, place, corporation or company. The 'people on the ground' are the people directly involved in the situation. This phrase is often used to talk about people in news reports who are living in an area where something is happening. The 'people on the ground' are the real, ordinary people affected by something.