The boundaries that are displayed will depend on the setup within the Command Center and whether or not the user has been assigned to a region, or a count team within a region.  In order for the tracts to be displayed they must be assigned to the region and/or count team by the count administrator (see instructions here).

If a user is assigned to a region, but not to a specific count team, the map will display the census tracts for the entire region which they are assigned to.

  If a user is assigned to both a region and a count team, the map will display the census tracts for the count team area they have been assigned to.
Counting Us region maps   Counting Us count team maps

Regions Using Geographic Sampling
Regions have the option of utilizing the geographic sampling and enumeration features within the Counting Us app and the Regional Command Center in order to derive an accurate estimate of homelessness in their area.  This approach, described here, enables the region to conduct a reliable count with significantly less volunteer resources.

If this feature is enabled then all the above rules still apply, but a different style is applied to the tracts to indicate their designation and whether they should be sampled. For an activity with sampling enabled and region/team management disabled, instead of seeing the outline of the activity geography, they will see all tracts in the activity, with the above mentioned styling applied.