It was a long day of lectures upon lectures, all on the tedious subject of local government finance, and even the unfailingly cheerful Hilda Pemberton, newly elected councilwoman from Prince George's, permitted herself to look a little drained.

"It's scary," she said last Thursday night. "If we don't get some state aid in Prince George's County, we're going to be in big trouble."

From the commissioners of rural Washington County to the mayor of industrial Baltimore, the talk of participants in the 12th annual conference of the Maryland Association of Counties (MACO) here was money--or, more to the point, lack of it.

After three days of seminars last week on the theme of maintaining essential services for fewer dollars, officials of Maryland counties said they were increasingly concerned about their ability to provide for their constituents in the face of continued high unemployment in pockets of the state, cuts in federal aid, and the expectation of little help from the state next year.

Most were united by fear that the Maryland government's projected $130 million shortfall complicates their own efforts to seek more state help, and might even mean future efforts to place greater financial burdens on them. However their individual problems are as varied as the local economies of 23 counties and Baltimore city.

"We're running on two cylinders: Mack trucks and Fairchild Hiller aircraft manufacturers ," said Ronald L. Bowers, president of the five-member Washington County Board of Commissioners. "They're both very hard hit by the economy."

As in other blue-collar and agricultural areas throughout the state, Bowers said, unemployment has floated between 14 1/2 and 18 percent over the past year in his western Maryland county, far higher than the 7.7 percent state average. Bowers himself is working a reduced schedule at the Mack truck plant, two weeks out of the month.

Baltimore Mayor William Donald Schaefer said that his city of 750,000, the state's largest, is already projecting a deficit of $42 million in the coming fiscal year and the possibility of cutbacks in a variety of services. "We really need assistance next year," he said. "The poor can't wait year after year." The city's property-tax rate is already at about $6 per $100 of assessed value, he said, about twice that of any other subdivision.

Other counties face less severe problems, but they are problems nonetheless. Despite a vigorous economic development strategy, Baltimore County has about 10 percent unemployment. "But it's more extreme than that," said County Executive Donald P. Hutchinson, "because it's concentrated in the southeastern part, with heavy industry like Bethlehem Steel."

Prince George's Executive Parris N. Glendening has repeatedly warned of a potential $30 million shortfall in his budget next year, as well as the possibility of layoffs of up to 600 employes if no more money is found. Hamstrung by the voters' rejection of a bill to loosen the county's strict property tax limit (called TRIM), Glendening has committed himself to seeking some type of additional taxing authority from the General Assembly this year.

Nevertheless, he faces some dissension at home from other officials who note that $19 million of that deficit is composed of projected salary and benefit increases for workers, in a year when state employes have been told that they will not receive a raise. Officials from other counties are also less than sympathetic to his plight because of TRIM, Glendening said.

By contrast, Howard County Executive J. Hugh Nichols said confidently, "We're in pretty good shape." With about 5 percent unemployment, and a fast-growing population of high-wage earners, Nichols looks forward to a year without a property tax increase--unless the federal government fails to renew the revenue-sharing program that expires in September. Loss of that money would mean adding 10 cents to the current property-tax rate of $2.39 per $100, he said.

Even affluent Montgomery County faces an $11 million deficit next year in its $750 million budget, according to County Executive Charles Gilchrist, largely because of a drop in interest income caused by declining interest rates, and decreases in the transfer tax from the sale of homes.

But despite the grim news, all was not bleak at the conference, whose participants filled up nearly all of the Hunt Valley Inn's 392 rooms. Officials sought out advice from panelists and shared ideas with each other.

They learned, for example, of low-cost consulting offered by the University of Maryland's Institute for Governmental Services, which will help them evaluate the quality of their programs, often for free. They heard of the Maryland Local Government Investment Pool, begun last month, which will invest their idle cash and help them increase their interest income.

Glendening and Schaefer met to hash over their legislative proposals, and other executives already had solutions in mind. Baltimore County's Hutchinson, for example, is experimenting with a program to retrain idled industrial workers for the growing high technology firms located in the northern county corridor. Montgomery's Gilchrist said he is considering imposing a video game tax, and raising the tax on nonreturnable beverage containers.

All officials were advised to be open with the public about their fiscal problems, and to "treat the media like gold."

"They are the key to getting your message across," said Hal Lefcourt, a Bucks County, Pa., public information officer.

Later, Gilchrist told reporters to put the budget problems in perspective. "It isn't as if the fiscal health of the state is in serious jeopardy," he said. "I don't want to give you the impression that we're all Perrier and quiche, but I think you can talk yourself into a worse problem by whining about it all the time."

Wallace Childs, a 17-year veteran of the Anne Arundel County Council and now its chairman, agreed. "In a way, it's worse than in the past because we don't know what to expect.

"But then again," he added philosophically, "we'll get by. I've seen this before."