From BiblePortal Wikipedia

Fausset's Bible Dictionary [1]

("house of the sun".)

1. A town on the N. boundary of Judah ( Joshua 15:10), itself low in situation. A "valley" of wheat fields is mentioned accordingly as nigh ( 1 Samuel 6:13). Now Ain Shems, on the N.W. slopes of the mountains of Judah, "a low plateau at the junction of two fine plains" (Robinson), two miles from the Philistian plain, and seven from Ekron. From the latter was the road to Bethshemesh, on which the Philistines sent back the ark to Israel after its fatal stay among them. In the field of Joshua the Bethshemite was "the great Abel" (the Septuagint reads Aben "stone"; others retaining Abel explain it "the stone of mourning," compare  1 Samuel 6:19) whereon the ark was set ( 1 Samuel 6:18). Providence fitly arranged that Bethshemesh being a priests' city ( Joshua 21:16;  1 Chronicles 1:59) had Levites and priests ready on the spot duly to receive the ark and sacrifice before it.

Curiosity tempted many to stare at (not necessarily "into") the ark beneath the cover; compare  Numbers 4:20;  2 Samuel 6:6-7. So God smote in the proportion of 50 out of the 1,000, i.e. one twentieth instead of one tenth of the population, as sometimes; seventy men in all, out of the population of Bethshemesh, which amounted to 1,400 in this view. The numbers in the English Bible are evidently a mistake ( 1 Samuel 6:19). Josephus (Ant. 6:4) makes it only 70. It was one of Solomon's commissariat districts under Bendekar (margin  1 Kings 4:9). Here Joash king of Israel encountered and made prisoner of Amaziah of Judah ( 2 Kings 14:11-13;  2 Chronicles 25:21-23). In Ahaz' reign the Philistines occupied Bethshemesh ( 2 Chronicles 28:18.) Ir-shemesh was the older name (compare  Joshua 15:10;  Joshua 19:41;  Joshua 19:43;  1 Kings 4:9). Harcheres, "mount of the Sun." was another name for Bethshemesh ( Judges 1:35.)

2. A city on Issachar's border ( Joshua 19:22).

3. A fenced city of Naphtali ( Joshua 19:38;  Judges 1:33). The inhabitants were not expelled, but became Israel's tributaries.

4. An idol sanctuary in Egypt ( Jeremiah 43:13), the Greek Heliopolis, Egyptian On, E. of the Nile, a few miles N. of Memphis ( Genesis 41:45). The statue in honor of the sun rose to 60 cubits, the base was 10, above there was a miter a thousand pounds weight. These many towns of this name show how widespread the worship of the sun had been.

Morrish Bible Dictionary [2]

1. A Levitical town on the north border of Judah, whither the ark was miraculously guided by God when sent back by the Philistines from Ekron, and where the people were smitten for looking into it. Here Amaziah king of Judah was defeated by Jehoash king of Israel. It was afterwards occupied by the Philistines.  Joshua 15:10;  Joshua 21 :16;  1 Samuel 6:9-20;  1 Kings 4:9;  2 Kings 14:11,13;  1 Chronicles 6:59;  2 Chronicles 25:21,23;  2 Chronicles 28:18 . Identified with Ain Shems, 34 59' E 31 45' N .

2. Border town of Issachar,  Joshua 19:22 . Identified by some with Ain esh Shemsiyeh, 35 31' E 32 24' N .

3. Fenced city of Naphtali.  Joshua 19:38;  Judges 1:33 .

4. Idolatrous temple in Egypt.  Jeremiah 43:13 . Supposed from its signification, 'house of the sun,' to be the same as On, or Heliopolis, associated with sun-worship.

Watson's Biblical & Theological Dictionary [3]

a city of the tribe of Judah, belonging to the priests,  Joshua 21:16 . The Philistines having sent back the ark of the Lord, it was brought to Bethshemesh,  1 Samuel 6:12 , where some of the people out of curiosity having looked into it, the Lord destroyed seventy of the principal men belonging to the city, and fifty thousand of the common people,  1 Samuel 6:19 . It is here to be observed that it was solemnly enjoined,  Numbers 4:20 , that not only the common people but that even the Levites themselves should not dare to look into the ark, upon pain of death. "It is a fearful thing," says Bishop Hall, "to use the holy ordinances of God with an irreverent boldness; fear and trembling become us in our access to the majesty of the Almighty."