Your dad was correct, the 18th Infantry Regiment definitely went ashore on Omaha Beach, France, on D-Day, 6 June 1944.
It was one of three Infantry Regiments (16th, 18th, 26th) in the 1st Infantry Division, First Army, to cross the beach that day.
The division departed NY P/E 2 Aug 42, on the QUEEN MARY, and arrived Gourock, Scotland, 7 Aug 42.
Sailing alone, it carried the entire division of 15,125 men, which was the first time an entire division had moved in a single movement.
From UK, the division proceeded to and assaulted North Africa 8 Nov 42; assaulted Sicily 10 Jul 43; returned to England 11 Nov 43; assaulted Normandy, France, 6 Jun 44; entered Belgium 3 Sep 44; entered Germany 15 Sep 44; remained active in Germany thru 1946.
Algeria-French Morocco, Tunesian Sicily, Normandy, Northern France, Rhineland, Ardennes-Alsace *, Central Europe.
One can see that this was a most experienced, battle hardened combat entity, and ready for such an undertaking as the invasion of Europe.
(* Unable to document 1st Infantry Division in Ardennes engagement in my references, however, the presence of the First Army is well documented, and this was the "parent" of the 1st ID).
Casualties (for all campaigns):
Killed in Action 3,616 Wounded in Action 15,208 Died from Wounds 664 Rate of casualties exceeded 125%
The following lists the elements involved in the D-Day operations at OMAHA BEACH:
First Army (Bradley) U.S. V Corps (Gerow) 1st Infantry Division (Huebner) 116th Infantry Regiment 16th IR 18th IR (The 16th and 18th hit Fox Beach in the vicinity of Colleville, France) 115th IR 2nd Rangers (Col. James Earl Rudder) (The 2nd Rangers hit at Pointe du Hoc) 5th Rangers 741st Tank Battalion 111th Field Artillery Battalion 7th Field Artillery Battalion 81st Chemical Battalion
Assaulting UTAH BEACH, France, was the
US VII Corps (Collins); 4th Infantry Division (Barton) 8th Infantry Regiment 22nd Infantry Regiment 12th Infantry Regiment 359th IR (attached from the 90th ID) 70th Tank Battalion.
In addition, the attack involved the 101st and 82nd Airborne Divisions as well as the US Eighth Air Force.
US Navy ships attacking or coordinating the attack on OHAMA BEACH included:
BATTLESHIPS ARKANSAS NEVADA TEXAS
Plus 3 CRUISERS, of which the AUGUSTA was the command ship for the armada Plus 30 DESTROYERS Plus 2 HEADQUARTERS SHIPS Plus 2 FRIGATES Plus 17 PATROL CRAFT Plus 9 MINESWEEPERS
Britain provided most of the line ships involved in the D-Day operations.
Other providers include France, Geece, Poland, Norway and the Neatherlands.
All of this plus "other vessels" including 4,126 Landng Ships and Craft; 736 Ancillary Ships and Craft; 864 Merchant Ships.
DEAR READERS: I HAVE THE LIST OF ALL SHIPS WHICH WERE ACTUALLY INVOLVED IN THIS LANDING AND FOLLOW UP, AND WILL BE PLEASED TO PROVIDE ANY INTERESTED PARTY WITH INDIVIDUAL SHIP NAMES UPON REQUEST TO firstname.lastname@example.org.
THIS COULD CONFIRM THE PRESENCE OF A FAMILY MEMBER ABOARD SHIP AT THE TIME.
CINDY JONES: Please refer to :
WORLD WAR II ORDER of BATTLE Shelby L. Stanton, author, GALAHAD BOOKS, NYNY, publisher
for an excellent Combat Narrative for the 1st ID. It does mention the 18th IR specifically.