California 49th Congressional District
You might also add a contextual note like (straddling Orange and northern San Diego counties) or Darrell Issa's seat.
Darrell Issa, one of my least favorite members of Congress--remember the outrageous "no women allowed" hearing on contraception he chaired in 2012?--has said he does not intend to seek re-election. Woohoo!
In a previously safe Republican district, Issa barely survived the November 2016 election, and he had been identified as the most vulnerable House Republican in a November 2017 poll.
[Edited to add a link to the poll, from Roll Call:
One Year Out: The 10 Most Vulnerable House Incumbents in 2018 ]
Issa had been facing some interesting Democratic challengers this time around. Democrat Doug Applegate, who almost unseated him last time, is running, and also 28-year-old Democrat Sara Jacobs, who is new to politics but was a State Department official in the Obama Administration. She is the granddaughter of Qualcomm founder Irwin Jacobs. So far, two other political newbies have expressed intent to run for the seat as Democrats.
A snippet from the New York Times article:
[H]is bare-knuckle partisanship had begun to wear on a district that is affluent and increasingly moderate. As chairman of the House Oversight Committee, Mr. Issa routinely ripped into Mr. Obama, his aides and his cabinet, as well as their handling of a gunrunning investigation known as Fast and Furious, the Internal Revenue Service’s slow-walking of political groups’ applications for nonprofit status, the terrorist attack on an American government compound in Benghazi, Libya, and many other matters.
A person familiar with the Republican effort to replace Mr. Issa said there was an expectation that several Republicans could enter the race, including Diane Harkey, a member of the California Board of Equalization, and Rocky Chavez, a member of the State Assembly.
The founder of a successful car-alarm company, Mr. Issa is one of Congress’s wealthiest members. But he became best known in Washington for turning the Oversight Committee into something like an Inquisition. He appeared to relish the role.