If four <grid-line> values are specified, grid-row-start is set to the first value, grid-column-start is set to the second value, grid-row-end is set to the third value, and grid-column-end is set to the fourth value.

When grid-column-end is omitted, if grid-column-start is a <custom-ident>, grid-column-end is set to that <custom-ident>; otherwise, it is set to auto.

When grid-row-end is omitted, if grid-row-start is a <custom-ident>, grid-row-end is set to that <custom-ident>; otherwise, it is set to auto.

When grid-column-start is omitted, if grid-row-start is a <custom-ident>, all four longhands are set to that value. Otherwise, it is set to auto.

The grid-area property can also be set to a <custom-ident> which acts as a name for the area, which can then be placed using grid-template-areas.

This property is a shorthand for the following CSS properties:

• grid-row-start
• grid-column-start
• grid-row-end
• grid-column-end

auto

Is a keyword indicating that the property contributes nothing to the grid item's placement, indicating auto-placement or a default span of 1.

<custom-ident>

If there is a named line with the name '<custom-ident>-start'/'<custom-ident>-end', it contributes the first such line to the grid item's placement.

Note: Named grid areas automatically generate implicit named lines of this form, so specifying grid-area: foo; will choose the start/end edge of that named grid area (unless another line named foo-start/foo-end was explicitly specified before it).

Otherwise, this is treated as if the integer 1 had been specified along with the <custom-ident>.

<integer> && <custom-ident>?

Contributes the n-th grid line to the grid item's placement. If a negative integer is given, it instead counts in reverse, starting from the end edge of the explicit grid.

If a name is given as a <custom-ident>, only lines with that name are counted. If not enough lines with that name exist, all implicit grid lines are assumed to have that name for the purpose of finding this position.

An <integer> value of 0 is invalid.

span && [ <integer> || <custom-ident> ]

Contributes a grid span to the grid item's placement such that the corresponding edge of the grid item's grid area is n lines from the opposite edge.

If a name is given as a <custom-ident>, only lines with that name are counted. If not enough lines with that name exist, all implicit grid lines on the side of the explicit grid corresponding to the search direction are assumed to have that name for the purpose of counting this span.

If the <integer> is omitted, it defaults to 1. Negative integers or 0 are invalid.

grid-area = 
  <grid-line> [ / <grid-line> ]{0,3}  

<grid-line> = 
  auto                                                |
  <custom-ident>                                      |
  [ [ <integer [-∞,-1]> | <integer [1,∞]> ] && <custom-ident>? ]  |
  [ span && [ <integer [1,∞]> || <custom-ident> ] ]   

HTML

<div id="grid">
  <div id="item1"></div>
  <div id="item2"></div>
  <div id="item3"></div>
</div>

CSS

#grid {
  display: grid;
  height: 100px;
  grid-template: repeat(4, 1fr) / 50px 100px;
}

#item1 {
  background-color: lime;
  grid-area: 2 / 2 / auto / span 3;
}

#item2 {
  background-color: yellow;
}

#item3 {
  background-color: blue;
}

Result

• Related CSS properties: grid-row, grid-row-start, grid-row-end, grid-column, grid-column-start, grid-column-end, grid-template-areas
• Grid Layout Guide: Grid template areas
• Video tutorial: Grid Template Areas