The Entrance

Source: The Great Pyramid Passages And Chambers" Volume 1 by John and Morton Edgar, 1910


Section 5.1.1

This old picture tells us a lot. First of all we can see the outer casing stones are more or less missing. On the right side at the basis you can see two originally placed casing stones. Under the two casing stones and to the left you can see the original pavement stones. The internal lime stones, which are the main part of the masonry, are therefore visible. Originally there were approximately 210 courses of  lime stones, but nowadays there are only 201. 
There are 3 "entries", it is easy to see two of them in the above picture. (All entries were originally covered by the casing stones.) 

The big entry in the top of the picture is a fake entry, its basis hit the 22nd course. Behind the huge stones there is, as far as we know, only lime stones. 

On the right side there is a hole made by the Arab caliph Abdullah al-Mamun in AD 820, which is the 2nd entrance (at 7th course).


The 3rd entrance is visible in the picture of an old drawing of this "fake" entrance underneath at the 19th course just under the "fake" entrance.

Source: The Great Pyramid Passages And Chambers" Volume 1 by John and Morton Edgar, 1910


Section 5.1.2

Underneath is a picture of a part of the drawing of the 3 entrances made by Edwards, so you can see how they are located:

Source: The Great Pyramid Passages And Chambers" Volume 1 by John and Morton Edgar, 1910


Section 5.1.3

If we ignore the big "fake" entrance and MamunĀ“s forced entrance, then we can focus on the 3rd entrance, which is named "ENTRANCE" on the picture above. This entrance was the original entrance to the passageways and the chambers inside the pyramid.