To get into a *median* ranked law school (meaning a school around the 50th percentile in US News & World Report rankings or similar), you'd generally need a very strong LSAT score, typically in the range of 150-160. The specific score needed will depend on many other factors like GPA, personal statement, letters of recommendation, and the specific school's applicant pool in that year.
To reiterate: The ACT is not used for law school admissions. Focus on preparing for the LSAT.