John Hanson Savings and Loan of Beltsville has grown to Maryland's third largest privately insured lending institution by sticking close to its home base of Prince George's County, expanding along with the rapidly developing county and merging with other institutions in the state.

Unlike other privately insured savings and loans, which tout their high interest rates in newspapers across the country, John Hanson advertises its rates, currently 8 percent on NOW accounts (interest bearing checking accounts) and statement savings, only locally.

"We're not highfliers," said spokeswoman Robin C. Staley.

John Hanson has more than quadrupled its assets during the 1980s to nearly $650 million -- behind Chevy Chase Savings and Loan with assets of $2.3 billion and the troubled Old Court Savings and Loan with $839 million.

The newest branch office, in Rehoboth Beach, Del., acquired earlier this year when John Hanson bought Milton Building & Loan, represents the institution's first foray outside the state. John Hanson merged with two other state savings and loans -- Eastern Shore Savings & Loan Association of Salisbury and Metropolis Building Association of Baltimore -- in 1981, and with Westowne Savings and Loan of Baltimore earlier this year.

During the last two years, John Hanson has participated actively in the "secondary mortgage market," working with the New York investment banking firm Salomon Brothers to acquire more than $100 million of mortgages from other institutions, according to executive vice president Kenneth V. Duncan.

John Hanson has close ties to prominent Prince George's County Republicans. Former county executive Lawrence J. Hogan is president and director of First Founders Financing Corp., a District mortgage banking firm 51 percent owned by John Hanson as well as a shareholder in John Hanson. Charles A. Dukes Jr., a Republican power broker and Hogan ally, is John Hanson's chairman and chief executive officer. Duncan is a former county chief administrative officer who held that job under Hogan and former county executive Winfield M. Kelly Jr.

Gerard F. Holcomb, a longtime Hogan confidant and Republican Party activist, is the institution's vice chairman. Holcomb made news several years ago when he lent personal funds at a high but not illegal rate of 104 percent annually to businessmen and developers -- including some John Hanson customers -- who had difficulty obtaining conventional loans.

Hogan played down John Hanson's political connections. "They're people who have been active in civic affairs," he said of bank officials.

John Hanson, named for the president of the United States under the Articles of Confederation, applied for federal (FSLIC) insurance last Friday. Spokeswoman Staley said bank officials were confident it would meet FSLIC standards, including the requirement that the institution's net worth represent at least 5 percent of its liabilities.

Staley said she did not know when approval for the insurance might be forthcoming but said it was not expected imminently.

John Hanson has been in good financial health in recent years. Net income for fiscal year 1984 was $9.6 million, up from $3.7 million in 1983. In fiscal year 1982, a bad year for the savings and loan industry, John Hanson lost $1.09 million, its only loss in 25 years. As of the end of April, profits for fiscal year 1985 were about $5 million.

Staley noted that 60 percent of John Hanson's loans involved residential mortgages, and that less than 3 percent of its funds was borrowed from outside sources. She said the bank had not been forced to dip into its lines of credit or to borrow from the Federal Reserve Bank in order to cover recent withdrawals.