Southern Cross Flags are flags which depict the Southern Cross. "Southern Cross" is the English name of Crux

Crux

Crux is the smallest of the 88 modern constellations, but is one of the most distinctive. Its name is Latin for cross, and it is dominated by a cross-shaped asterism that is commonly known as the Southern Cross.-Visibility:...

, a constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 visible in the Southern Hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

. It is also depicted in coats of arms

Coat of arms

A coat of arms is a unique heraldic design on a shield or escutcheon or on a surcoat or tabard used to cover and protect armour and to identify the wearer. Thus the term is often stated as "coat-armour", because it was anciently displayed on the front of a coat of cloth...

 of various countries and sub-national entities. This star constellation is visible mostly in the southern hemisphere and it therefore symbolises the southern location of its users.

The term Southern Cross can also refer to the blue saltire

Saltire

A saltire, or Saint Andrew's Cross, is a heraldic symbol in the form of a diagonal cross or letter ex . Saint Andrew is said to have been martyred on such a cross....

 as used in various flags of the Confederate States of America

Flags of the Confederate States of America

There were only three flag designs adopted, with later, minor variants made to those designs, that served as the official national flags of the Confederate States of America and used during its existence from 1861 to 1865...

 in the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

.

This is an incomplete list and some of the flags in this list might not have official status. Also, note that flag proportions

Flag terminology

Flag terminology is a jargon used in vexillology, the study of flags, to describe precisely the parts, patterns, and other attributes of flags and their display.-Description of standard flag parts and terms:...

may vary between the different flags, and sometimes even vary between different versions of the same flag.