Are there any scriptures (Dharma Shastra-s) or Hindu saints who have talked about patriotism?
Related: This post discusses specific to Kshatriya class, Martyr concept in Hinduism
The Vedas, in particular, do not have a limited (narrow) vision of patriotism. The Vedas clearly say that we all are the children of Mother Earth. Hence, we should love the whole earth as our motherland and not just our own country.
MAta Bhumih Putro Aham PrithivyAha .
The earth is my mother, I her son.
Atharva Veda Samhita, Kanda 12, Sukta 1, Mantra 12.
In Hinduism, Earth and Bharatvarsh is considered as mother. And, in general, everyone love their mother.
Vishnu Purana says:
उत्तरम् यत् समुद्रस्य हिमाद्रे: चैव दक्षिणम्।
वर्षम् तद् भारतम् नाम भारती यत्र संतति:||
THE country that lies north of the ocean, and south of the snowy mountains, is called Bhárata, for there dwelt the descendants of Bharata.
Earth is also known as consort of Lord Vishnu, so very respectable. There is a shloka regarding this.
समुद्रवसने देवि पर्वतस्तनमण्डले ।
विष्णुपत्नि नमस्तुभ्यं पादस्पर्शं क्षमस्वमे ॥
Samudra-Vasane Devi Parvata-Stana-Mannddale |
Vissnnu-Patni Namas-Tubhyam Paada-Sparsham Kssamasva-Me ||
1: (Oh Mother Earth) The Devi Who is having Ocean as Her Garments and Mountains as Her Bosom,
2: Who is the Consort of Sri Vishnu, I Bow to You; Please Forgive me for Touching You with my Feet.
Vishnu Purana also praise Bharatavarsh as:
गायन्ति देवा: किल गीतिकानि, धन्यास्तु ते भारतभूमिभागे।
स्वर्गापवर्गास्पद - मार्गभूते, भवन्ति भूय: पुरुषा: सुरत्वात्।।
The gods themselves exclaim, "Happy are those who are born, even from the condition of gods, as men in Bhárata-varsha, as that is the way to the pleasures of Paradise, or the greater blessing of final liberation.
There are shlokas in Hindu scriptures which may be interpreted as patriotic.
It seems that the gods sing songs to this purport. Those who live in this part of the world called Bharata are in fact blessed. In order to enjoy the fruits of heaven and salvation they are born as human beings, casting off their deity-hood.
[Garuda Purana, Dharma Khanda, chapter I]
The best mention I think is the one mentioned by The Destroyer in comment :
जननी जन्मभूमिश्च स्वर्गादपि गरीयसी ||
meaning :One's Mother and Motherland are more glorious than the heaven.
Reference : According to Wikipedia, this line is from the Valmiki-Ramayana :https://en.m.wikipedia.org/wiki/Janani_Janmabhoomischa_Swargadapi_Gariyasi