There's no official, globally recognized height that determines if a landform is considered a mountain. It's more about relative elevation and prominence than an absolute number.

Here's a general breakdown:

* Mountain: A landform that rises significantly above its surroundings, with a summit reaching at least 1,000 feet (300 meters) above sea level. They often have steep slopes and a defined peak.

* Hill: A landform that rises above its surroundings, but generally less than 1,000 feet (300 meters) above sea level. They typically have gentler slopes than mountains.

Important Considerations:

* Prominence: This refers to how much taller a peak is than the lowest point along its surrounding ridgeline. A peak with high prominence is considered more significant, even if it's not incredibly tall.

* Local Context: The definition of a mountain can vary depending on the region. For example, in some areas, a landform might be considered a mountain even if it's only a few hundred feet tall, because it stands out significantly compared to the surrounding landscape.

Ultimately, there's no hard-and-fast rule. It's more about how a landform appears and its relation to its surroundings.