K. is a determined land surveyor who arrives at the village claiming to have been summoned by Castle authorities. Driven by a steadfast belief in logic and administrative protocol, he expects to be officially recognized and put to work. His pride and self-conviction are immediately tested as he encounters the perplexing, obstructive reality of the village residents and the distant Castle administration.

Frieda is a diminutive barmaid with a surprisingly superior gaze and an ambitious demeanor. As Klamm's mistress, she commands a level of prestige and power among the village women, using her position to act with pride and authority. She quickly involves herself with K., creating an immediate social complication regarding his standing with both the villagers and the Castle authorities.

Klamm is an elusive and powerful director at the Castle. Described as a medium-sized, ponderous gentleman with a smooth face and sagging cheeks, his presence dominates the village despite his severe physical detachment. He represents the impenetrable bureaucracy that K. must confront to legitimize his presence.

Barnabas is a young messenger assigned to deliver communications between K. and the Castle authorities. Though his initial appearance inspires hope, his actual standing and effectiveness in managing the Castle's system are questionable, leaving K. frustrated by unclear messages.

Olga is Barnabas's sister, possessing a gentle and tranquil demeanor that calms K. during his chaotic arrival. Her peasant family lives in severe poverty and faces community isolation, causing her to seek alliances and carefully protect her siblings.

Amalia is the youngest sister of Barnabas and Olga. She is fiercely proud, aloof, and responsible, bearing the brunt of her family's difficult social standing in the village without complaining or seeking pity.

Gardena is the landlady of the Bridge Inn. Having been Klamm's mistress over two decades ago, she remains deeply devoted to his memory, keeping three faded mementos of their brief time together. She is highly protective of Frieda and deeply suspicious of K.'s motives for entering their lives.

Artur is one of K.'s two assigned assistants. He lacks surveying equipment or knowledge, instead spending his time engaging in playful, useless antics that constantly test K.'s patience.

Jeremias is the second of K.'s unhelpful assistants. He mirrors his partner's frustrating behavior, shadowing K. while contributing nothing to the actual work of surveying.

Schwarzer is the son of a Castle steward. He uses formal, administrative language to assert authority over newcomers and initiates the first stressful telephone inquiry regarding K.'s credentials.

Momus acts as Klamm's village secretary, handling all written work. He attempts to take a formal deposition from K., enforcing the tedious bureaucratic procedures favored by the Castle.

Pepi is a young, attractive, and deeply ambitious chambermaid who temporarily takes over Frieda's position in the taproom. She is highly critical of Frieda and eager to elevate her own status with the Castle gentlemen.

The village school teacher is a strict, officious figure who offers K. a demeaning job as a school janitor to keep him occupied while K. awaits official word regarding his surveying post.

Hans is a charming young schoolboy who shows sympathy for K. and Frieda's harsh living situation, offering a potential back-channel connection to his influential parents.

Otto is Hans's father and a master shoemaker who reportedly advocated for a surveyor, making him a potential ally for K. despite his current hostility.

Gerstäcker is a frail old coachman who offers K. brief moments of assistance and transportation through the snowy village, often hoping to secure personal favors in return.

The village chairman is a verbose local official who explains the tortuous, highly inefficient history of K.'s summons, demonstrating the utterly convoluted nature of Castle bureaucracy.

Count Westwest is the unseen ruler of the Castle. His permission is supposedly required for anyone to reside in the village, representing the highest and most distant peak of power.

The landlord of the Bridge Inn is a nervous and subservient man who defers heavily to his wife, Gardena. He acts anxiously regarding Castle regulations and officials, terrified of causing offense.