A quick search on "112th Infantry Regiment" and "28th Division" brought up over 48,000 sites that tell something about the unit and the major battles they participated in, including WikiPedia.
I'd start with a couple that show up on the first coule of search pages and get a good idea of specific area to focus in on and the time frames your grandfather was with the unit.
And if your grandfather is no longer living, you may want to contact the National Archives and get a copy of his service record.
Not in WW2. Before 1939, each US Army Infantry Division had 4 infantry regiments. This proved to be too large for use on the battlefield. So the size the division was reduced and one regiment was removed. So the 3rd Infantry Regiment could have been part of a Division before then. However, during WW2 the 3rd Infantry Regiment was not part of an infantry division. Source: http://www.custermen.com/ItalyWW2/ArmyOrg/OrgChart/Divisions.htm
Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie company was sent to the village of my lai, and us soldiers were ordered to kill the villagers as they never knew who was in the viet cong or on the opposition to them .
My father was injured near Soun-ni, Korea, on 15 October 1951. He was in Company F, 19th Infantry Regiment, 24th Infantry Division.
Vijayabahu Infantry Regiment was created in 1988.
Singapore Infantry Regiment was created in 1957.
Not in WW2. Before 1939, each US Army Infantry Division had 4 infantry regiments. This proved to be too large for use on the battlefield. So the size the division was reduced and one regiment was removed. So the 3rd Infantry Regiment could have been part of a Division before then. However, during WW2 the 3rd Infantry Regiment was not part of an infantry division. Source: http://www.custermen.com/ItalyWW2/ArmyOrg/OrgChart/Divisions.htm
15th Infantry regiment, 3rd Infantry Division (US Army) and 36th Infantry Division (Texas National Guard)
You need to be more specific about whether you're referring to the 7th Infantry Division, or the 7th Infantry Regiment before this question can be answered.
Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade, 23rd Infantry Division (the Americal Division), arrived in South Vietnam in December 1967 Charlie company was sent to the village of my lai, and us soldiers were ordered to kill the villagers as they never knew who was in the viet cong or on the opposition to them .
My father was injured near Soun-ni, Korea, on 15 October 1951. He was in Company F, 19th Infantry Regiment, 24th Infantry Division.
In WWII it belonged to the 26th Yankee Division. Part of the 3 rd Army.
Mechanized Infantry Regiment was created in 2007.
Singapore Infantry Regiment was created in 1957.
Mechanised Infantry Regiment was created in 1979.
Vijayabahu Infantry Regiment was created in 1988.
Bangladesh Infantry Regiment was created in 2001.
Fiji Infantry Regiment was created in 1920.