Department store sales across the country rose 8 percent in March over sales a year ago, the U.S. Commerce Department reported yesterday.

Sales in the Washington area rose 11 percent during the same period, the report said, which tied it for second highest increase among the nine standard metropolitan statistical areas with department store sales of $100 million or more.

According to a Commerce Department spokesman, part of the increase could be due to an increase from 94 to 104 in the number of stores serving the metropolitan area. Department stores were defined as those with 25 or more employes that sell furniture and appliances, a general line of family apparel, household linens and dry goods with none accounting for more than 80 percent of total sales.

The Washington area includes the District, Charles, Montgomery and Prince Georges counties, the cities of Alexandria, Fairfax and Falls Church and Arlington, Fairfax, Loudoun and Prince William counties.

Sales in March increased from $106.085 million last year to $117.714 million this past March, the Commerce report said. The area with the largest increase, 15 percent, was Dallas-Forth Worth, Tex., which had $114 million in sales. The largest sales, $273 million, up 11 percent, were reported in the Los Angeles-Long Beach area, according to the report.

For instance Woodward & Lothrop Inc. in Washington reported first quarter sales increased 11 percent but profits declined by 7 percent.

The May Co. Department Stores, owner of Hecht's in Washington and Baltimore, reported a sales increase of 15 percent and an increase in profits of 30 percent during the first quarter of this year.