And he judged Israel in the days of the Philistines twenty years.Jud 13:1,5 16:31
He seems to have judged South-west Israel during twenty years of their servitude of the Philistines.

Bible Gateway: Judges Chapter 15 Verse 20 NIV ESV NKJV NLT KJV Message Amplified
Alphabetical: days for he in Israel judged led of Philistines Samson So the twenty years
New American Standard Bible Copyright © 1960, 1962, 1963, 1968, 1971, 1972, 1973, 1975, 1977, 1995 by The Lockman Foundation, La Habra, Calif. All rights reserved. For Permission to Quote Information visit http://www.lockman.org.
GOD'S WORD® is a copyrighted work of God's Word to the Nations. Quotations are used by permission. Copyright 1995 by God's Word to the Nations. All rights reserved.
OT History: Judges 15:20 He judged Israel in the days (Jd Judg. Jdg) Christian Bible Study Resources, Dictionary, Concordance and Search Tools
Judges 15:20 Bible Software
Judges 15:20 Multilingual Bible
Judges 15 Parallel Chapters
Online Parallel Bible