People living in the West were the most likely to have been crime victims last year while residents of the Northeast were the least likely to have been victimized, the government says.

Nationally, crime levels in the United States rose 1.8 percent in 1987, ending a five-year decline, the Bureau of Justice Statistics reported Sunday.The number of criminal victimizations rose some 613,000 in 1987 to more than 34.7 million, with increases compared to 1986 in the amount of both personal and household crime.

Even with the increase over 1986, there were 16 percent fewer crimes last year than in 1981, the peak year for crime with 41.5 million criminal victimizations, said Joseph Bessette, the bureau's acting director.

In 1986, the number of crimes hit the lowest level in the 15-year history of the government's national crime survey, 34.1 million.

Last year, the number of personal crimes rose nearly 250,000 or 1.4 percent from 1986 to just over 19 million, with increases in all four categories of rape, robbery, assault and theft.

The number of household crimes rose by nearly 360,000 or 2.3 percent to 15.7 million, with increases in burglary, larceny and motor vehicle theft.

Reagan administration officials have tried to depict declines as a result of sterner law enforcement and a more cooperative public. Some academic experts analyzing the data have stressed that the size of the most crime-prone age group, those in their middle to late teens, has grown smaller in the 1980s.

The numbers of personal crimes per 1,000 people last year were 125 in the West, 101 in the Midwest, 91 in the South and 71 in the Northeast. The household crime figures per 1,000 residents were 223 in the West, 166 in the Midwest, 179 in the South and 116 in the Northeast.

The West was the only region to show an increase in the personal crime rate last year compared to 1986, up 8.6 percent. In the South the rate fell by 4.8 percent, while the Northeast and Midwest showed no significant change.