The 45th Infantry Division traces its roots to the Oklahoma Territorial MIlitia which was formed in 1890. Elements of the Oklahoma Militia were called upon to suuport operation in Cuba during the Spanish American War and the 1st Oklahoma Infantry Regiment fought in the Mexican Border Conflict in 1916. This Regiment was formed after Oklahoma was admitted to the Union in 1907.

In 1920, the 45th Infantry Division was formed from elemments of the National Guard units of Oklahoma, Colorado, Arizona and New Mexico. When it was first formed, the Division wore an ancient symbol of good luck, the swastika. When Hitler came to power, the division wisely adopted a new symbol, the Thuderbird.

In September of 1940, the Thunderbirds were called into FEderal service to conduct training operations for a period of one year. By the time that year was up, their service was extended as ware seemed more ane more likely. At the end of 1941 and all of 1942, the 45th Division conducted numerous training cycles inTexas, Virginia, Massachusetts and New York. Finally, in June 1943, the 45th Division boarded troop transports and set sail for Algeria, North Africa. For the next month, the division underwent intensive amphibious training for its combat debut; the invasion of Sicily

July 1943 found the Thunderbirds storming ashore at Sicily. For 45 straight days, the Thuderbirds battled the forces of Italy and Germany for control of the island. Resistance was stiff, but the invaders continued to push and the island was finally secured. In September of 1943, the 45th participated in another amphibiouslanding, this time at Salerno on the Italian mainland. For several days, the Thunderbirds pushed inland and finally captured Cassino where they were relived for a much needed rest and resupply.

Yet another amphibious landing was asked of the Thunderbirds, this time at Anzio. When the 45th Divison landed they were opposed by seven German Divisions. Unfortunately, the landing force took too much time consoldiating its positions that the Germans were able to bring up reserve forces and launched a major counter offensive. For the next five months, the Thuderbirds and the rest of the invasion force held on to their fragile beachhead in furious attacks and counter attacks. Finally the Allied forces were able to break the German lines at Monte Cassino and the Anzio invasion forces broke through and linked up. One month later, the Allied forces, with the 45th in the lead, capture Rome. The 45th sttod down for another well deserved rest.

For a 4th and final time, the Thuderbirds conducted and amphibious assault, this time in Southern France in August of 1944. After successfully establishing a beachhead, the 45th quickly formed up and began a drive inland. Within months they had liberated the key city of Alsace, France, had smashed through the Siegfried Line into Germany and had captured the city of Nurnberg, the same city where Hitler's National Socialist (Nazi) party had held their anual conferences. One week before the German surrender, the 45th Division marched into Munich.

During World War Two, the Thuderbirds had fought for 511 days and had compiled quite a combat record. They had captured over 126,000 prisoners at a cost of 28,000 casualties. They were credited with 8 campaigns from 4 amphibious landings. 8 Thunderbirds were awarded the Medal of Honor. After the war, the 45th was returned to National Guard status

In 1950, the 45h was called to action for the Korean War. They were on of two National Guard Divisions to see action in the war. (the other being the 40th Infantry Division of the California National Guard) Throughout 1950 and into 1951, the 45th brought in new troops to fill its ranks and was transferred to Japan to finish its training. Almost 70% of the Division had combat experience from World War Two, mostly in leadership positions.

In December of 1951, the Thunderbirds arrived on the Korean peninsula and took up defensive positions in the Tonchon-Chrowon areas. Their primary mission was to hold their sectors and drive off any enemy advance. All through 1952 the 45th engaged in numerous small battles at Old Baldy, Pork Chop Hill, Heartbreak Rdige, and other places along their sectors. In every instance the Thuderbirds held their ground and the North Koreans never broke through. By the end of 1952, the Guardsmen of the 45th began rotating back home after their two year terms ended and were replaced by active duty soldiers. The division remained in Korea until the peace accord was signed and was then deactivated back to National Guard status. In 1969, the Division was disbanded and reorganized as the 45th Separate Infantry Brigade of the Oklahoma National Guard. The Brigade conducted numerous training exercises.

Only one unit of the 45th saw action during the Persian Gulf War, the 1st BY of the 158th Field Artillery. The battery was the first National Guard unit to fire on the Iraqi defenses and was called upon to support the 3rd Armored Division the 1st Infantry Division and the 2nd Infantry Division. In all the 1-158th fired 903 rockets onto Iraqi defenses and was instrumental in breaking up their positions for the armored and infantry forces.

Today the 45th Brigade is part of the 7th Infantry Division as an enhanced Brigade along with 2 other National Guard Brigades, the 39th and the 42nd.