John H. T. Briscoe, 90, a former trial magistrate and state's attorney in St. Mary's County who had practiced law in Leonardtown for many years, died of pneumonia Friday at St. Marys Nursing Home in Leonardtown, where he had resided for about a month after suffering hip fractures.

He was of counsel with the law firm of Briscoe, Kenney and Kaminetz in Leonardtown, founded by his son, John Hanson Briscoe, until shortly before his death. Earlier, he had maintained his own law practice for many years.

Mr. Briscoe was chief trial magistrate in St. Mary's County in 1971 when Maryland replaced the trial magistrate system with a new district court system. Mr. Briscoe had sat as a magistrate since 1964.

"The magistrate courts have been the courts of the people," he said then. "Now we're getting away from the idea of the peoples court -- we'll hve new rules, new procedures -- a dignity which will be above the heads of the people who have to use the court."

Mr. Briscoe had served as state's attorney for St. Mary's County from 1920 to 1935 and again from 1948 to 1954.

Active in Maryland Democratic politics, he had been a member of the Maryland House of Delegates from 1940 to 1944, and was a former chairman of the Democratic Central Committee of St. Mary's County.

Mr. Briscoe was born in Hollywood, Md. He was a graduate of Loyola College in Baltimore, where he played varsity basketball. He started his law practice in Leonardtown in 1916. He resided in Hollywood.

Survivors include his wife of 57 years, the former Hilda Wade of Hollywood; his son, John Hanson of Hollywood; three daughters, Hilda B. Dale and Maria (Lou) Gardiner, both of Hollywood, and Adriana (Meme) Gillaspy of Spencer, Ind., 14 grandchildren and two great-grandchildren.