MEMORANDUM ORDER

MARK L. HORNSBY, Magistrate Judge.

Calvin Hobley was killed in an accident at a KCS railroad crossing. Hobley's surviving wife and children ("Plaintiffs") filed suit in state court against KCS and the Louisiana DOTD. KCS has removed the case based on an assertion of diversity jurisdiction. It acknowledges that Plaintiffs and the DOTD share Louisiana citizenship but argues the citizenship of the DOTD should be ignored pursuant to the improper joinder doctrine, which is outlined in Smallwood v. Illinois Central RR Co., 385 F.3d 568 (5th Cir. 2004). The court is obligated to determine subject matter jurisdiction, including whether a party is improperly joined, either through a motion challenge or on its own initiative. Gasch v. Hartford Acc. & Indem. Co. 491 F.3rd 278, 281 (5th Cir. 2007). The court issued an order (Doc. 6) that directed Plaintiffs to file a motion to remand by November 9, 2018 if they contest the assertion that the DOTD was improperly joined. The order stated that if Plaintiffs did not timely file a motion to remand and challenge the improper joinder plea, the court would consider Plaintiffs to concede the point, and the DOTD would be dismissed.

The November 9, 2018 deadline has passed, and Plaintiffs have not filed a motion to remand or otherwise challenged the improper joinder plea. Given the concession, the court finds that the DOTD was improperly joined. When a court makes such a determination, the improperly joined party must be dismissed without prejudice. International Energy Ventures Mgmt., L.L.C. v. United Energy Grp., Ltd., 818 F.3d 193, 209 (5th Cir. 2016). Accordingly, all claims against the DOTD are dismissed without prejudice for lack of subject matter jurisdiction.