Employment and personal income data are not the only measurements of economic health, but they are two of the key ingredients.

Government reports published last week show that the Washington region is continuing to show unusual strength in both, pointing to a good year ahead for the local economy.

Only Florida and Alaska recorded greater increases in personal income than in the District of Columbia during the third quarter of 1980, the Commerce Department reported. Nationally, real personal income rose 3.1 percent in the July-to-September period from the previous three months.

Maryland's gain was the same as the national average, but Virginia personal income rose 3.2 percent and D.C. personal income was up 4.4 percent. Total personal income in Virginia topped $50 billion in a three-month period for the first time in history, a level exceeded among states in the Southeast only by Florida.

In terms of year-to-year personal income growth, Virginia was up 10.7 percent, while both D.C. and Maryland rose 9 1/2 percent.

Personal income includes not only salaries and wages but also interest and dividend income rentals and other labor income. a

Employment in the metropolitan area, meanwhile, rose in December while the number of persons out of work declined slightly. Since the work force normally expands a bit during holidays as retailers hire part-time workers, the rate of area unemployment in December stood unchanged at 4.3 percent when adjusted for seasonal variations. d

Metropolitan unemployment was 66,900 compared with 69,200 the previous month and about 65,000 a year ago, based on figures published in 1980 that currently are being revised. The 4.3 percent level of unemployment contrasts with the national average of 7.4 percent, which has been fairly constant since last spring.

The important news is the number of area jobs filled: 1,588,800 in December compared with about 1,545,000 a year ago and not counting military personnel.

The troubling news is the continued weakness of the District economy, in terms of jobs for city residents: 292,300 in December compared with 295,100 at the end of 1979. Local government employment in D.C. declined 4,700 in the past year; and there were declines also in transportation, communications, public utilities and the federal government work force offset partially by gains in services, banking and food manufacturing.

For the greater Washington region as a whole, however, unemployment continues to be less of a problem than elsewhere in the nation, although the trend in Maryland shows the impact of recession in that state's key manufacturing sector.

Maryland unemployment rose to 6.2 percent in December, the first increase in 1980, the state Department of Human Resources said last week. The unemployment rise from 5.9 percent in November was caused by slow business conditions and the seasonal trend of manufacturing firms laying off workers for Christmas and layoffs in construction, food processing and agriculture.

The state agency also said more people entered the job market in December in search of holiday season employment. But the December unemployment rate, although higher than November, was lower than the 6.4 percent rate of December 1979.

Baltimore metropolitan-area unemployment rate also rose in December to 7.1 percent from November's 6.8 percent while in the Washington suburban counties, unemployment remained steady at 3.6 percent.

South of the Potomac, some 19,000 Virginians were out of work in December, but the jobless rate of 4.9 percent was the lowest since May and the best December rate sice 1973, a Viriginia Employment Commission official said.

William Mezger, assistant director of manpower research, said December's slight drop from November's 5 percent rate could have been the result of fewer Viginians seeking work during the Christmas season, because of the "belief that few jobs were available because of the recession."

Mezger said retail employment, however, was slightly higher than last year because of gains in food stores, restaurants and speciality shops. Mezger also said mild weather the first three wees of December caused fewer than the usual number of cutbacks in outside works.

The state's lowest December jobless rate was 2.8 percent in Northern Virginia. The Norfolk-Virginia Beach-Portsmouth area had a 5.3 percent rate, the highest.

New layoffs since the first of the year in Virginia have occurred in the textiles, furniture, auto parts and building materials industries that had difficulties in 1980.