What milestone is usually reached when a child can sit unassisted for a long time?

The ability for a child to sit unassisted for extended periods typically indicates that they have reached significant developmental milestones related to core strength and balance. Most children are able to sit independently without support by around 6 to 9 months of age. However, consistently sitting unassisted for longer durations is generally seen closer to the 9-month marker.

At this point in development, infants have usually developed the necessary muscle control and coordination to maintain an upright position, enhancing their ability to explore their environment visually and interact with toys and caregivers. This milestone is critical as it forms the foundation for further motor skills, such as crawling and eventually walking.

While some children may achieve this skill slightly earlier or later, the 9-month mark is a standard developmental guideline used by pediatricians to assess growth and developmental progress.