The Pennsylvania Supreme Court on Monday released a new congressional map, which will be used for 2018 elections. The map is likely to be challenged by Republicans, who have indicated they'll fight it in federal court, sources say.

The map was ordered to be redrawn by the state Supreme Court in January, when it determined the current district boundaries, drawn in 2011, were unconstitutional due to gerrymandering in favor of the Republicans.

Multiple sources say Republican leaders in the General Assembly are expected to attempt to challenge the map, but as PennLive.com reports, "unless and until they actually prevail in that challenge, these are the new lines effective with the 2018 election cycle."