The collection of all the regions of a baseline are contained in the AeccBaseline.BaselineRegions property.
The Autodesk Civil 3D API does not include methods for creating new baseline regions or manipulating existing regions.
The following sample displays the start and end station for every baseline region in a baseline:
Dim oBaselineRegion As AeccBaselineRegion For Each oBaselineRegion In oBaseline.BaselineRegions Debug.Print "Baseline information -" Debug.Print "Start station: " & oBaselineRegion.StartStation Debug.Print "End station: " & oBaselineRegion.EndStation Debug.Print Next