To be involved, you need to know what districts you live in for US House of Representatives (which with the US Senate comprises the US Congress) and for the PA General Assembly (= PA Senate and PA House). For which precinct you should vote in (find that here).
As of Feb. 2018, all Chester county is in one US House district, PA-06:
(See the prior, gerrymandered map here.)
Find Chesco school districts here.
For a map of each PA House and Senate district with the list of municipalities and precincts in each , see here.
Download a map of Chesco with all its PA Senate districts here: PA State Senate districts 2014-
Download a map of Chesco with all its PA House districts here: Chesco PA House districts 2014
For convenient reference and printing, download a pdf of municipalities and precincts in each district (2 pages, no maps) of Chesco districts here: PA districts Chesco 2015–
Download an Excel list of each Chesco precinct with its Democratic zone, US House district, PA senate district, and PA House district here: Chesco Zones and Districts 2014-2020