What do you mean by contiguous sites?

Touching, neighboring or adjacent localities

Contiguous States are states that share borders with other US states.

Similar to states, contiguous counties are counties that share a common boundary and they often span more than one state. However, some are separated by water ways such as lakes or rivers and may not technically "touch" without a gap. That happens when the official county boundaries only extend to the edge of water-way but not to its center. Although not technically contiguous, most still count it as so.